Yikes! Something broke, don't know what or how to diagnose!

[Seadoobuddy]

Now that is one long sentence and he's not even done yet....whewwwwwwww!!

LOL

 

[Sink]

With the compression reading being low but equal I would say the gauge is inaccurate and the compression is ok verify the gauge accuracy first before pulling engine apart I have three compression gauges and all three read different on the same engine u get what u pay for u bought a cheap gauge so is not a great gauge but the equal reading seem ok I also think u might just have a boost leak a tear in a hose or one popped off I would go over and check all the intercooler piping for a Loose clams or ruptures

+1 They are all even. If something happened compression wise, they wouldn't be even. The same thing wouldn't happen exactly the same to all cylinders.

You said the engine was running rough. That means something is probably happening in ONE cylinder and not the others. Compression thats low and even wouldn't act like that. It would still run even but have no power. Sounds more like you lost ignition in ONE cylinder. I would sure start with spark. Check that you have spark at each (plug). (sorry but I had to say it). You have separate coil packs so it could be a plug or a coil. Don't be so dam stubborn. You are ignoring experience here. Trouble shooting is a science. You need to KISS. ALWAYS check the easy things first. (Would really SUCK if you replaced the plugs and it ran fine, wouldn't it???)

I'll offer $500 for the broken ski!

 

[Michael211_2000]

I've had the entire SC hose pop off the carb before... other than ~250 rpm reduction, from 0 to 30mph the engine ran just fine no misses or surging or anything. Less horsepower of course, but otherwise the engine runs just fine without the SC boost.

I actually bought the only compression test guage I could find that has the correct size spark plug adapter... I didn't have any choices on this thing. Nobody pointed me to a better one when I asked....

The head bolts are all tight I just finished checking them just to be sure. (whew!) Nothing seems out of place under the valve cover. I found by Googling, some threads talking about timing and how that can affect cylinder compression... timing is not something I'm real good at, is it possible the timing chain jumped a cog when I was running near 70 mph?

Guys I'm not pulling this engine apart until I have some reason to pull it apart... trust me, I'm going no deeper than the valve cover until there's a suspect. LOL!

I guess I can uncover the jetboat and stick the compression gauge into one of the BBC 454 spark plug holes and see what it reads? It's the easiest motor I have here I can test it on.... unless a lawn mower engine would work? My pickup engine is too hard to reach the spark plugs, I'd rather not use it.

Thanks.

Crisso, Dave... agree that we disagree on the spark plugs for now guys. There's no need for hard feelings; I have indication the engine compression is bad and so I need to know the compression is right 1st IMHO. Now group hug! :grouphug: We all want the same thing, to enjoy our watercraft as much as possible and help others whenever possible.

- Michael

 

[Seadoobuddy]

A mower will work, but IDK the right PSI for them.

OK stupid question....did you release the air pressure from the gauge between testing all cylinders?

 

[Michael211_2000]

Who's broken ski are you talking about? Not mine I hope! LOL!

Well look the very 1st suggestion I had on this issue the night after it went to running so bad was to compression check the cylinders... it took several days to find a compression guage with the right sized fitting for the spark plug hole (a week actually of going by all the local auto parts places seeing what compression guages they had). Then I got seriously side-tracked on other more pressing matters.. yesterday I *finally* got those cyclinder compression numbers and they are very very low apparently.

So now should I simply ignore the guage and the numbers it gave me or what? I was very alarmed and suprised to find all 3 cylinders are so much lower than they should be... everything I'm reading says they should have ~150 psi and be fairly close to one another for the engine to run right.

What's a good way to check the spark on each coil/plug? Can I just pull each coil and plug 1 at a time, stick the plug in it's coil and crank the engine while looking at the plug end for a spark? Will they still spark if I'm holding WOT to prevent the engine from starting? IDK.

Ahhhh heck, I'm just going to go pull all 3 plugs out and stick them in their respective coils and try cranking WOT and see what they do... the seats have been off for some 2 hours by now, I'll have a waterhose and fire extingisher close at hand just in case it catches fire as a result of any sparks. Let's see what happens shall we?

- Michael

 

[Michael211_2000]

A mower will work, but IDK the right PSI for them.

OK stupid question....did you release the air pressure from the gauge between testing all cylinders?

Yes, on #1 and #3 cylinder tests... #2 cylinder I forgot to press the button on the guage to release the pressure before unscrewing the spark plug adapter, it let all the pressure blow out the spark plug hole when the adapter came out. No biggie. But it means there is no need to press the button on the guage to release the pressure when going from 1 cylinder to the next as all the pressure will be lost when you unscrew the adapter out of the spark plug hole.

Gonna go play with the plugs and coils for a minute now... be back shortly with more info!

- Michael

 

[Seadoobuddy]

I have a Craftsman gauge. The end looks like a tire valve...lets pressure in but not out until I release it myself.

 

[Michael211_2000]

Good spark!

Ok,

1st, I checked all 3 spark plugs and coils as per attached pic... I only had 1 ground wire to use so I did them 1 at a time, and every one of them sparked a blue arc from electrode as the engine turned over (and there I am cranking the engine watching the plug spark as gasoline/air mixture is blowing out of all 3 cylinders right by my face... fun, fun!). So they're all sparking, the coils must work and so must these plugs I presume. Correct?

Next, I took the compression guage and pulled a spark plug out of my pickup engine (a BBC Vortec 454) and installed the spark plug adapter and guage... I could only start the engine at idle, I could not go WOT because the other cylinders were running and I cannot reach the distrubutor to unplug the hot wire! At idle though, that cylinder read 118psi. I don't know what it would read at WOT.

Next, I took the compression guage and pulled the spark plug from my 12 hp Kawasaki lawn mower engine, which I could crank at WOT since it only has the 1 spark plug anyways. Cranking it at WOT the guage only read 65 psi... pretty low, but don't have a clue what the cylinder compression is supposed to read on this small engine.

So that's all I know at this point. All my 5 hr use spark plugs fire and the blue arc looks good.

Is the guage calibrated correctly you think, or should I take it back to O'Reilly and get my ~$40 back? I still have the receipt and they've been pretty good about warranty'ing things.

Thanks.



- Michael

 

[Michael211_2000]

Ok I made a Fupar.... just before sunset this evening I happened to open the spare spark plugs holder in the rear tray to see if last year's spark plugs were indeed in there.... bugger! The plugs in the spare spark plug holder are bright shiney new with the electrode caps still on them. I could have sworn I changed the plugs when I changed the oil and oil filter before winterizing it last October, but evidentally I didn't cause there they are staring at me. So the plugs I've been running are actually last years plugs and I don't know how many hours are on them but they look so clean I thought they were the new plugs.

Anyways I went ahead and swapped the old plugs for the new never used plugs real quick. Just for grins I'll plug a waterhose into the flush port Saturday and start it up to see if it runs any differently with the new plugs in it. I wish it was that simple really I do, but I rather doubt they'll change anything. Will update this tomorrow afternoon sometime.

Regards!

- Michael

 

[crisso]

Michael
Mate .change whatever.After reading the thread the other day about a blown blower pipe,it could be either.A very small crack or leak could have a big impact on perf.Since you said in your post,it happened after a full on blast.it may be a blower pipe with a tiny crack or hole.Hope all goes well.
CHANGE THE BLOODY PLUGS:lol:

 

[crisso]

Well done.Posting about the plugs.Take my hat off to you

 

[Michael211_2000]

Ya'll are really fixated on spark plugs... :toetap05:

Ya didn't happen to read my last posting, did ya?

I went ahead and swapped the old plugs for the new never used plugs real quick. Just for grins I'll plug a waterhose into the flush port Saturday and start it up to see if it runs any differently with the new plugs in it.

The old plugs were all 3 sparking though when I tested them Friday afternoon, so I fail to see how changing the plugs can possibly make any difference but I would NOT complain if by some chance this did fix the problem... the old plugs look almost exactly like the new plugs, just not quite as shiney but the eletrodes are in perfect condition.

I either don't have a blower pipe or have no clue where this pipe is located. If you're talking about the supercharger to carb hose, that ain't the problem the engine's symptoms were MUCH more extreme than simply loosing boost it was taking almost full throttle to just get it to go 20 mph to get me back to the docks and it was missing and surging extremely hard the entire way. As I've posted repeatedly now, I KNOW how the engine runs when it looses SC boost I was having a problem earlier this summer with the SC to carb hose popping off the carb it looses some rpm's and some horsepower but it's not so bad that you can't keep riding it and having fun the engine just becomes more like a 155hp non-supercharged engine instead of the 215hp supercharged engine it is. This is not that, I promise I was there ya'll! LOL!

- Michael

 

[Michael211_2000]

Well done.Posting about the plugs.Take my hat off to you

Well I'm not trying to hide anything here... it is what it is, I thought I had put the new plugs in last Fall when I winterized the engine but now it's obvious I didn't. Ooops!

I'm workin on a pot of coffee here, when I get done I'll go out and hook her up to a waterhose and test run it on the trailer and see if I can tell any difference or not... would sure be easier to verify changes if I could put it in a body of water and run it under load, but that's just not possible right now and believe it or not we're back under high-fire danger warnings again here! Makes me VERY nervous, so many homes burned up not far from me the other week I could see the smoke from the Tri-county wildefire near The Texas Reniassance Festival grounds every day to my west, luckily nobody I knew lost their homes but people I knew were evacuated for over a week because of the fires this is a bad bad situation I swear.

btw: Is there any other way to verify the calibration of these engine compression guages? It's just air pressure, I wish I could figure a way to use a tire pressure guage on the engine compression guage to see if the numbers are about the same or not. Hmph! I may have to see what a hardware store can come up with to let me add a tire valve stem into the guage so I can verify it's readings.

- Michael

 

[ski-d00]

to check compression, you do NOT have the engine running. hold the throttle wide open, this will keep it from sparking and starting. keep plugs in the other 2 cylinders and crank until the gauge reading maxs out. 4 tec compression can vary greatly even from the factory, it all depends on how the cam gear position is set and this can be set on either of 2 teeth with tons of adjustability as well. I've seen compression from 110 to 160 and will run very well. the racers will adjust the cam gear to get max compression. check all 3 cyls and as long as they are close to each other, that is the most important thing.

 

[crisso]

Sorry mate but Aussie homor is anal.We will keep on it ,just for the fun.
I read every word of your post.I put that there to stir you up.It worked.Sorry

 

[crisso]

The reason you hold it at WOT is so the piston draws the maximum amount of air into the combustion chamber.with NO restrictions such as throttle butterfly valves or choke valves.Or piston valves if you wish to go to another type of engine setup..Do the math

 

[crisso]

Ya'll are really fixated on spark plugs... :toetap05:

Ya didn't happen to read my last posting, did ya?



The old plugs were all 3 sparking though when I tested them Friday afternoon, so I fail to see how changing the plugs can possibly make any difference but I would NOT complain if by some chance this did fix the problem... the old plugs look almost exactly like the new plugs, just not quite as shiney but the eletrodes are in perfect condition.

I either don't have a blower pipe or have no clue where this pipe is located. If you're talking about the supercharger to carb hose, that ain't the problem the engine's symptoms were MUCH more extreme than simply loosing boost it was taking almost full throttle to just get it to go 20 mph to get me back to the docks and it was missing and surging extremely hard the entire way. As I've posted repeatedly now, I KNOW how the engine runs when it looses SC boost I was having a problem earlier this summer with the SC to carb hose popping off the carb it looses some rpm's and some horsepower but it's not so bad that you can't keep riding it and having fun the engine just becomes more like a 155hp non-supercharged engine instead of the 215hp supercharged engine it is. This is not that, I promise I was there ya'll! LOL!

- Michael

How can you say EVERY person here is wrong when you cant find the blower tube.Really mate.Learn which side your bread is buttered on

 

[Michael211_2000]

to check compression, you do NOT have the engine running...

Uhhh, I didn't have it running and I was holding WOT where are you reading that I did otherwise?

You guys totally lose me sometimes I swear... lol!

We just want to know if the guage I have is accurrately calibrated or not, that's all. All 3 4TEC cylinders were at 90 psi (maybe #1 was 89.5 psi, it was very very close to 90psi!).

- Michael

 

[Michael211_2000]

How can you say EVERY person here is wrong when you cant find the blower tube.Really mate.Learn which side your bread is buttered on

You're taking my sentences out of context. IF the "blower tube" or "blower pipe" isn't the Supercharger to Carb hose, then NO I have no idea if I have one or where it might be found it's not in the service manual or the online micro-fiche's I've studied. You seem to be using different terms for the same thing with every post... how am I or anybody supposed to follow you? Are you talking about a blower tube or a blower pipe and is that the same thing as the hose that goes from the Supercharger to the Carb or not? Answer the question, please!

Be consistent with your terms or else nobody can understand what you're referring to, mate!

And you betcha, EVERY person here who thinks I'm loosing boost pressure from the supercharger IS wrong... guess what, I was there riding the thing I know what it was acting like and it was far far worse than any loss of supercharger boost. I have experienced loss of boost before when the hose popped off the carb, and that is NOT this. I know more about the symptoms this machine is exhibiting than ANYBODY here, cause I was there riding the machine when this all started early last month.

Amost nobody seems to be giving any consideration to the symptoms I've described, some people are shooting from the hip making a quick post to this thread without actually *reading* what the symptoms are or what I've actually done to try to figure this out so far... like why am I being told once again how to properly do the engine compression test when I've already described exactly how I did the engine compression test and I did it correctly as per the very 1st time it was described to me? Nobody has pointed out any fault with the procedure I used, they just keep telling me again how to do it like they didn't bother to READ how I just did it? LMAO! ROF! :rofl:

- Michael

 

[Michael211_2000]

Ok I just ran it on the trailer w/water hose for 3 or 4 minutes... I cannot tell if the change of plugs made any difference or not really. I think I'm going to have to swap the plugs back and run it on the trailer with the other plugs again to be able to make a better comparison... it seems to be running pretty rough with the new plugs above idle still, but I'm not sure if it's better or the same as with the previous plugs. Grrrrr!

- Michael

 

[Michael211_2000]

After switching back to the original last/season's plugs and running it a few minutes, then putting the brand new 0 hrs plugs back in and running it a few minutes, I believe it does run smoother with the new 0 hrs plugs. Idling it up with the new plugs, I'm not sure if the engine is still surging or I'm just unable to hold the throttle *exactly* still without a load on the pump... I need to put it in a body of water and test ride it to determine if the new plugs have solved the problem or just smoothed out the idle. I don't know anywhere I can launch from in the Houston area now though, all the boat launches I'd traditionally use are land-locked with the drought... this may have to wait awhile before I can confirm if it runs right or not. For now I went ahead and re-installed the seat bridge though so everything is nice and buttoned up again. I'd love to test ride it and have it perform right again before winterizing it this year!!!

While reving the throttle I did reach down and grip the supercharger to carb hose and squeezed it so could feel the pressure in the hose, so it is making boost for sure and I could not feel any air leaks between the supercharger and the carb while making boost.

ps. I've been getting that chattering sound when reving the engine on the trailer (doesn't make the sound when in the water or at idle on the trailer), so I think over this winter I'm going to go ahead and replace the carbon ring I'm sure it's running the original 5 year old one and it may be time.

Regards.

- Michael

 

[Fat Cat]

Wow, read the ENTIRE thread to find that it is most likely plugs. What a waste tbh. :|

 

[Michael211_2000]

Wow, read the ENTIRE thread to find that it is most likely plugs. What a waste tbh. :|

Maybe, not sure. Will have to wait till I can get it in the water and test drive it. It wouldn't hurt my feelings none if it was just a spark plug problem, even though I would not understand that at all.

And your comment makes this thread even longer yet adds... nothing. Good going!

Regards.

- Michael

 

[crisso]

Mate.Wait untill you get it backed into the water.All skiis run good on the trailer without load on the engine.
I have gone back and read this thread from start to bloody finish
You said that you refuelled the ski.The problems you are having MAY ,and I underline MAY,and it sounds like.No fuel getting to the motor.Very clean plugs can indicate this.Nothing burning is leaving no deposits.
OR,read this again,OR,water in the fuel.Water in the fuel will make any motor run like a lame goat.They will cough,fart and splutter.Just as you put your problems.
Now my friend.I AM NOT saying this is the final fix.I am saying this can also give you your engines problems.Its a process of elimination.
Just as we make you laugh at our responses,you also do the same for us with your replies.
Now CHANGE THE BLOODY PLUGS :lols:

 

[underwdr]

I need to know!!!!!Did you ever conclusivly find out what was wrong????