Everyone please chime in on these exhaust pictures...

[seadoosnipe]

I agree!

The ECU could very well be over correcting causeing a lot more oil to be used than what's necessary. But I don't think that would explain the drop in the compression like that. I did review your other post about the hot starting, etc...to see if there might be some correlation between those problems and the ones your seeing now in the compression drop. I'll also be waiting to see your next set of results from another test. Do it with the engine cold.
The compression....if you had a drop, say in the center cylinder and the other two were 10 pounds over, then I'd say you might have a bad cylinder and will need to be re-ringed. If you had a bad head gasket, blown between two cylinders, then you might get good compression on one and low on those two, but for all three to be almost equal......makes me want to believe there something else to it......hopefully a bit more simple, just finding it.
I've asked Don, "Wheels and Waves" to come back in and take a look at your compression. He owns a PWC shop and specializes in the Rotax engines, but a mechanic is a mechanic and I'm sure he'll be able to off a little more input as to what we can be looking for.
I did look at your exhaust system and both heads discharge into the center seperated by a baffle plate. There doesn't seem to be anything there that would allow the exhaust gases to cross over to create a compression reading that would be equal.
I have done a lot of reading on the lubrication system. I'm thinking there may be a connection to the way the oil pump is shafted to your crankshaft.

I'll be curious as to what Don's opinion is. Hopefully he'll have a look by tomorrow.

 

[scarfie]

Second Compression Test...

Now I'm baffled. Here are the results of the 2nd test:

Port top: 125psi
Port middle: 122psi
Port bottom:125psi
SB top:135psi
SB middle:135psi
SB bottom:135psi

It's a colder day than last time I did it. Would that make a difference?

So with this test, each cylinder is within 15 psi of each other as the manual states they should be. However it's still apparent that something is up with the port side.

Maybe Don will have an answer or two.

 

[seadoosnipe]

Compression

Yeah, I always check compression with a cold engine. That way, the rings have just enough lubrication to make a seal. If your compressing oil and gas and your ratio of oil is a bit high, then your more likely to lose some of that compression through the rings. You can compress a gas a lot easier than you can compress a liquid. This compression test is better and with those readings, I don't think your piston rings are causing the oil smoke. I'm still hoping Don will see your post and give his opinion. I've sent him PM to come by and look.
At the moment, I'm trying to focus on the oil pump. I think the next step will be to try the oil pump test again for the volume of flow. I noticed the this gear type oil pump is geared off the crank and it seems that it's also on the same side that has the lower compression. There is an "O" ring that seperates the oil side of this pump and your crankshaft. If this is bad, then you could be dumping extra oil into the crank from that point. That's why I asked you if you were using a bit more oil than you thought you should be.
How do your plugs look? The difference between the 2,4 and 6 plug verses the 1,3 and 5?.....

 

[scarfie]

Didn't compare plugs from one side to the other...

Then I accidently dumped them on the deck of the boat so now they are all mixed up.

I planned on doing the oil flow test as well but this time i need to take the boat out and warm it up first. last time I did it with the hose connected in the yard.

That gear that connects to the shaft that runs the oil pump should not be allowing any oil through to the shaft correct? (actually the oring you mention should not allow it). If it is leaking oil into the shaft instead of flowing through the pump, that would account for low oil flow. That would also mean I've been running a low mix.

That would also explain why it still smoked like crazy when running off 50:1 premix with the oil pump output hose disconnected. The more i write the more I think I will not run it without premix until I figure out what's up with the oil pump.

What would be the procedure for pulling the oil pump altogether and then running premix to see if the exhaust clears up?

 

[seadoosnipe]

Good ideas!

It seems your onto some good ideas. But I think I would pull the oil pump to check the "O" ring before deciding on going with premix. I don't think you did any damage to the engine because if that is the problem, then you were still delivering oil to the vital areas of the motor.
I'll be going in tonight for the grave yard shift. I have your manual at work from the last time I was trying to help you trouble shoot. Trying to recall the procedure in removing that pump, I don't think it was much more than disconnecting the oil lines, pulling the two bolts and removing the pump....but let me check the manual. I'll get back with you later this evening.....
Seems like you told me that you are a second owner and haven't had it that long. Do you have any history of the boat that might help us? For the most part, your compression is good and you've said that the motor doesn't miss a lick, just smokes. I'm remaining optimistic that the issue is not serious....it's just gonna take a bit of "process of elimination" before we find out what's going on.
I'm kinda workin in the blind here since all I have to go on is the manual. I've never worked on this type engine or for that matter, seen one close up. Almost my entire experience is based on the Rotax engine......so, we'll be learning together. I just don't want you to have to take it to the shop and spend millions on getting it repaired. Before you ruin a 4 or 5K motor, it may be your last resort.......but I ain't done tryin to figure it out.......
I'm also going to read up some more on all the sensors that signal the ECU to see if this could be an area of concern. I know you said you had the temp sensor out to be replaced. I've noticed there is a check valve in the oil line that recieves pressure from the crankcase to push the oil up to the pump. What if this check valve is bad, maybe the oil could be flowing backward into the crank......I'll get more details on that too so that you can check it.
Write more tonight......

 

[scarfie]

I have the procedure...

...to remove the oil pump. You are right, two hoses and two bolts. There is also the throttle link rod that has to be detached.

I need to get a smaller socket set for the two bolts. Plus I need some locktite and a torque wrench to put it back together. Guess I'll run to the store. I'm running out of light so I guess I'll get an additional work light, too.

I really am itching to see how the o rings look. Where the pump attaches is right in the middle of the side with low compression on the cylinders. You may be on to something here.

Maybe I'll have an answer for you before your night shift is over.

 

[scarfie]

A little more than I bargained for tonight...

Everything always looks easier on paper. Iwas able to get the two hoses and two bolts out and get to the first o ring. I will not be able to get to the throttle link unless I remove the vapor seperator and it's collection of hoses - that's too much to get into tonight.

I'll never get the second bolt back in without removing the vapor seperator because it took some maneuvering to get it out. I'll give it a go again tomorrow.

I'm looking at the larger o ring. It looks OK but I think I'll replace them both just to be sure. I still didn't get a look at the smaller one so maybe it is the culprit.

One thing I won't understand until I have all the parts in my hand is that the big oring popped right out. I actually didn't see it until i looked down and saw it laying on the bilge. From what I see on the diagram, I'm not supposed to see the big oring yet.

I don't know, I'll have more to report when I get the linkage off and the pump in my hand.

 

[seadoosnipe]

The drawing?

Yeah, when I was looking at the drawing and saw that the oil pump was on the same side that the lower compression test was, I thought the same thing. But in reality, it's geared to the crank where all the connecting rods are attached. In other words, centrally located. I first thought there might be some relation to it myself. But we'll wait to you check the "O" rings and see what you come up with.
BTW, I'm sending you a PM.

 

[seadoosnipe]

Oil Pump removal?

No, your right, there are only four steps. You should just have to un-do the lines and plug them, then take out the bolts and it should just come right out. The "O" ring you saw may have been one on the worm gear. When you get to that point, look at those "O" rings really good. Especially the one between the oil side housing and the worm gear shaft.
The book doesn't show that the seperator should be in the way....but you know, it's never as easy as the book makes it out to be......
Keep me informed of where you stand.......

 

[seadoosnipe]

Check valve?

I've been reading into the chapters of the oil and fuel system. There is one other thing I'll be wanting to see you take a look at. There is a check valve at the crankcase that provides one way protection that will allow to much oil to mix with the fuel or allow oil to run backward into the crank.
I haven't heard from you in a few days, so I'll assume your working your butt off. Give me a holler when you get a chance........let me know how things are going........"outside of slow"...I know.
Sometimes troubleshooting can be a real pain in the u-know-what.

 

[scarfie]

Parts will be here Friday (2 new orings along with the new bushing). Work was crazy today and I didn't get a chance to remove the Vapor Seperator so I could finsh removing the oil pump, but I figured for 15 dollars or so, I'd go ahead and replace those parts regardless of their condition.

Which page are you seeing this check valve and how do I test it. I'll look through the manual again.

I might be able to get to the rest of the disassmbly tomorrow and will let you know what the second o ring looks like.

I'll be putting it back together late Friday / early Saturday and will take it for a test run sometime Saturday. I'll also have the new head temp sensor which I will replace while I'm on the water after seeing if the fuel pump parts do anything.

One good thing out of all this, I've gotten in pretty good with a Mercury repair and parts place at a Marina just down the street. Their part prices are the same as what I've found online, and they can get them quicker. Plus, if I end up having to bite the bullet and take it into the shop, maybe they'll cut me a break knowing what I've done already. Don't want to bite the buillet...don't want to bite the bullet.

BTW - I replied to your PM...in case you didn't see it.

 

[seadoosnipe]

post?

I just lost my complete reply to your post, with this dumb, antique computer I use at work. We are a leading manafacturer of semiconductor grade polysilicon for the computer industry and they supply us with junk that went obsolete 10 years ago!.........:rofl:
Anyway, in a nut shell, I told you that the pages in your manual that cover that check valve are on 3E-6 and 7. I've read the complete chapter and find it interesting. I'm at a point where I think we'll find the smoke problem in this oil/fuel system. I think your ratio of 50:1, that is suppose to be running your engine is out of whack. It may be the pump, or this check valve, or the "O" rings in the worm bushing....but I feel pretty certain it's not in the pistons.
Good to get to know that Merc parts guy. Always better to make new friends than enemies. Maybe he can shed a little light on what he may think is going on.
The only Seadoo parts place around me is run by one owner and he charges about 125% more than he paid for the part....I order my stuff online.
BTW, we may have already touched base on this question in an earlier post but what type of oil are you using? It is an NMMA, TCW-3 oil isn't it. I think we talked about this already cause you were asking about the Quicksilver brand.........refresh my memory if you don't mind.

 

[scarfie]

Everything is back together and...

...no luck. The exhaust is still smoking like crazy.

Here's what I did. I replaced the worm bushing in the oil pump with a new one (new o-rings as well). The old bushing was not moving freely and was hard to pull out of the pump. The old o-rings looked OK - no noticable tears or anything.

I cleaned the pump and inspected the worm gear inside the pump, which looked fine. I then put the pump back on and adjusted the throttle link to the pump because it was a bit out if whack. I throttled up and down to make sure the pump was returning to where it was supposed to be at idle. Everything checked out so far.

To get to the pump, I did have to remove the vapor separator. Here is something I found with that:

To remove the separator, the first step is to relieve pressure using a schrader valve before you empty the separator via the drain plug. There was no pressure being released when I pressed in the schrader valve. Don't know if that is an issue or not, but I checked it two more times later on with the same result.

I also changed the fuel filter between the gas line and the primer pump, checked compression again (120 psi on the starboard side, 130 on the port side this time), properly gapped and installed new plugs, started crossing fingers and went for the external fuel tank.

With all that done, there was no fuel in the separator, the pump or the line. I decided it was a good time to try a 50:1 premix from the external tank before hooking up the oil pump output. I cranked up the motor on the premix and the exhaust was BAD. I didn't even try to leave it running for the 15 minutes required to complete the oil flow test...didn't want the fire department or the EPA police hitting the neighborhood.

Before I started with the premix, I put a little bit in a clear plastic bottle so i could see its color. After running the premix only through the first time, I drained the seperator into another clear bottle. The premix that came out of the separator was a lot darker than the premix before it went into the engine. Is this normal?

I tried hooking up the oil pump output and regular fuel line. Ran it just enough to enjoy the billowing exhaust all over the neighborhood (sarcasm) and then drained that mix out of the separator into a 3rd bottle. It was the same dark color.

SO...that's where we stand. I'm starting to wonder if there is a cylinder not firing or something. Maybe it has something to do with check valve, but I really believe it is something different only because the 50:1 premix does the same as the oil injection mix. Could be I didn't tear the pump down far enough to the bearing and driven gear...it may still be leaking somewhere further in than the worm bushing.

Guess this post is long enough. Any ideas on what to look at next?

 

[seadoosnipe]

Been Out!....

Sorry man, bee taking a break the last couple days and haven't really gotten in to do much work.
It sounds like you covered a lot of bases and we're only into half of the troubleshooting. You ask if you can have a dead cylinder....If you had a dead cylinder, then yes, it would create smoke.....but you've said in the past that the engine ran fine, that it only smoked bad coming off plan into the idle area of your throttle. You seem to be a real capable mechanic since we've started your trouble shooting but out of just wanting to check all our bases; are you familar with the sound of an engine running on a dropped cylinder.
The issue of the oil coming back into the seperator a different color, that makes me wonder if there is still much oil going to the engine. Also, your compression results aren't so far off that the engine would run so smokey. I also want to do further reading into your exhaust system and this seperator your talking about. I think, after you check and make sure the check valve coming from the block isn't sticking open, we'll be able to say that you've gone through the entire oil injection system and the problem doesn't originate there.
You mentioned that the engine still smoked really bad when you went on the temporary tank. Does the temporary tank run with the oil and fuel system on the boat completly shut down? These systems are completely isolated from the boat? Also, I noticed in the pix you posted that the oil smoke comes from both exhaust ports. On a car, twin exhaust is hooked up to each bank of the engine. Therefore, if there was smoke on the drivers side, then that meant the 4 cylinders on that side of the engine had a problem.
I'm going to look a bit further into your exhaust system to see if there is anything we can narrow down to by smoke from both ports.
I know I've asked before but don't remember you answering......what kind of oil are you using in the injection tank?...........
I'll hope to be on again later this evening!.........

 

[scarfie]

That's alright...it took me a while to get everything done anyway. I guess you could say I'm competent but not a mechanic. I have done hardly anything in the way of motor diagnosis. I'm learning as I go.

I'm not exactly sure what an engine sounds like running on a dropped cylinder. At high RPM is sounds like it's running on all 6 - it's just smooth as can be. At idle it's a little on the rough side. Every few seconds it will sound like it's skipping or missing a beat. Isn't that just the way of a two stroke?

How do i check the check valve? Is it just a visual thing or do I need to physically take it off and check that it opens and closes?

When I ran off the temporary tank I did have the main oil and fuel completely shut down. The fuel line from the main tank was disconnected. I also disconnected both the in and out hoses from the fuel pump.

The oil I'm using is Mercury Precision Plus...the stuff that is recommended in the manual.

Thanks for keeping up with this thread. Working on the engine, I was DONE with it today...real frustrated. The biggest thing is that I don't know what to move on to diagnosis next. Guess the check valve is next on the list.

 

[seadoosnipe]

Frustration!

I can understand your frustration but the number one piece of advice a shade tree mechanic would tell you is that patience is the only way you'll win the war on this engine wanting to screw with your head. You seem to be or becoming a pretty good mechanic on this engine.....Stay with it. If it gets to the point that we've tried everything, then you may have to bite the bullet and get it to the shop. But we got a few more things on the list that need to be gone over.
I'm really enjoying keeping up with your post because like you, I don't have a lot of the M2 engine under my belt, so it's a learning curve for me too. But before I advise you to do something that may cause harm or terminal damage to your motor, I'll tell you to stop and seek professional advice. But for now....lets keep going.
The check valve. If you have that drawing in your manual. See if you can find the hose that is coming from your engine to your oil tank. That's the hose that uses the pressure off the crankcase to build pressure in your oil tank. It's suppose to have a one way check valve in it. If you can identify this hose, remove it, then with the end of the hose cleaned off and protected, see if you can blow through it. If you can blow through it, then the check valve is stuck open. This will need to be repaired or fixed. This will be the last thing in the oil injection system to check. From here, if it isn't the check valve. I'll want to move to the fuel injection system. It seems a bit more simple with less mechanical parts to check. We'll be mostly wanting to pay attention to where the oil mixes with the fuel before it goes into the engine.
A dropped cylinder......this would be something I would have checked in the beginning, but I guess I took it for granted that you may have already done that. This isn't a problem....real easy to check. For me, I'd start the motor and take a plug wire off, one at a time. If there was a dead plug or cylinder, you'd notice in the sound of the engine right away. As your taking the plug wires off one at a time, you'll notice for example, the first wire you took off....there was no change in the tone or vibration in the motor. Then after taking off, say one or two, you take off the one that's dead. You'll notice right away, there was no change in the engines sound or vibration. This is your dead cylinder. This is entirely possible. If you got a dead cylinder, the oil is not being burned off in the piston. SO this would really be the next step I'd take, even before checking the one way valve on the oil tank.
Let me know what you find out. Let's find and fix this problem together. If we get if done and your motor works great without smoking, you'll have to invite me over for a T-bone steak, hot off the grill!..........I like Porterhouse by the way!.....................

 

[scarfie]

You know, first thing in the morning I'm going to refill the gas tank on the grill just to start the day off right. I have a family member who raises angus cattle so I'll scare up the best damn porterhouseyou've ever tasted.

Mechanically the biggest thing I've ever successfully worked on is an 18 speed bicycle. I screwed up a weedwhacker once. Didn't know where to start with the M2 and didn't even think about a dropped cylinder until a couple days ago.

I'll start there tomorrow.

 

[seadoosnipe]

Get back with me!

Let me know what you find out. And they do make a specific tool you can use for testing the spark on a cylinder..........you can buy it at your local auto parts store....
Be careful, don't get zapped by a plug. It's something you'll only do once!....I promis you...

 

[scarfie]

Louis,

I think we can put this thread to rest! Sunday morning, I replaced the head temperature sensor on the starboard head and the temp sender on the port head. Dropped the boat in the water and cranked it up.

It still has quite a bit of exhaust until it warms up but after that the exhaust is not bad at all at idle. Every once in a while it would be a little more than I cared for but I could throttle up and back down and it would be about what I'd expect out of a two stroke.

I think two things did the trick:

1) adjusting the throttle linkage to the oil pump. It was quite a bit out of whack at idle position and was probably pumping too much oil at idle.

2) the head temperature sensor. I tested this twice and the tests showed that it was not working. I believe that the control unit had no idea that the motor ever warmed up and kept pumping a cold mix at all times. Hopefully this will help on gas usage as well.

The new plugs perked it up as well. Got a solid 6000 rpm and 52 mph out of it. Lord knows I don't need that much speed all the time but with the wife and dog not on board, it sure felt good to open it up to see what it would do.

I'm still going to check the check valve just to feel 100% about the oil injection system. I'll report back on it when I do it.

There were no cylinders missing when I checked that. I could hear exactly what happened when I pulled a plug wire. I pulled tham all one by one and determined that it was firing on all cylinders.

I really appreciate you helping me through this. It's nice to get this familiar with the motor so when things crop up in the future I have a chance of finding the problem and fixing it.

Tell me where to send the porterhouse and I'll overnight you one.

I'm going to start another thread on a question I've had. Nothing urgent...just need some information for when this motor finally kicks it and needs rebuilding or replacing. Hopefully that will be years down the road.

 

[seadoosnipe]

Over joyed!

I'm really happy that things are coming together for you on the M2. This is a very expensive motor to buy off the shelf. When you first posted and we knew the temperature sensor was bad and you had ordered the part, I felt a certain degree that this part could very likely be the trouble. For the same reasons you said. The ECU/M and all the other electronic sensors on this motor does all the tuning as the motor is running.
So all that you've learned and all that you've written back to me is useful information for you to continue to keep your motor running in excellent shape.
It's been an informative learning session for me on this type engine.
Please feel free to PM or post any time you need something. I believe the smoking issue will probably clear up a lot more once all the additional oil is burned off.
I'll take the Porter house T-bone when we do the greet and meet. You just show up and we'll all have a beer together and talk about all the fun (pains) that we've all gone through.
Take care!