97 Challenger slow...

[Dr Honda]

if you are going to run the boat out of the water... mix up a little soapy water, and squirt it in the carbon seal. it needs something to lube it so it doesn't overheat. Soap is the recommended lube, but I normally just put a little coating of waterproof grease on the face of the seal. Also... be careful to not over heat the engine. Like I said above... 15 or 30 seconds... that's it. Personally... I think the second test is a waste of time. You should be seeing a MUCH higher pressure reading cold.

Oh... just so you don't get any bad info from a local mechanic... do not put any oil in the cylinders. It will seal up the rings and give you a higher reading... but it's not a real reading. Also... I am assuming it is cranking at a normal speed. If the engine is cranking slow... you will get low readings. But if it's cranking fast enough for a normal start... then you are OK.

OK... the impeller... your answer is unacceptable. If you want a Skat-Trak... order one from the states, and be done. Shipping down to Oz isn't that bad for a small box. It's about a 5x5x5 inch box, and only weighs a few pounds. I know I've shipped control levers down there, and I think it was only around $13 USD for US postal, and took 6 days. UPS, FedEx, DHL will probably start around $40, and only take 3 days.

But... if you just want to support the local economy ... that's cool, but you will be limited on what you will find.

Anyway... let us know what you find in the engine.


One last thing on this post... did you buy the boat from an individual who happens to be a mechanic... or did you buy it from a shop? If you bought it from the shop, I would check your local laws to see if there is any way to get some of your money back, or have them actually rebuild the engine because it was sold under false pretenses. (they lied)

 

[Hollymax0428]

Thanks Tony. Yes I really am only doing the 2nd compression test just to guage an idea of what is going on. I figured if it was rings only I should see some improvement, if it was something else bottom end it would stay the same even warmed up.

I agree there is a lot of difference in the psi being 115 and being 140-150.
I've pretty much resolved myself to that fact the head and cylinders need to come off this weekend.

I have ordered a Solas Concorde SD-CD-14/22 impeller locally and should be here tomorrow. You are right, yesterday after having some much trouble finding suppliers in Oz and seeing so many available in the US, I thought in the end I would just get one out from the States. This one will give me a better indication at least before I start pulling the motor apart, and it seems to be a fairly common prop for the 720 motor, so if need be I shouldn't have much problem selling it.

I actually bought the boat from a guy who bought it 12 months earlier from the Jetski Mechanic (& is also very good friends with the mechanic). This guy sold it because he had 2 other Jetskis and didn't have the time to use it??.
The thing that got me was both had used the boat within the last 10 hours of a motor rebuild, with a worn prop & wear ring that had 45-50 thou clearance, and that wouldn't have happend in just 10 hours, surely.
Both seem quite genuine and I would say if it came to having to do repairs both would come to the party and make it right.

That part isn't my problem, my time is and I really wanted to spend the time I have using it, not fixing it. We are right in the middle of our summer so getting a boat into a repair shop that takes up the room of 4 jetskis would be hard & I'm not that sure I could trust someone else to do it, besides I have completely pulled apart & rebuild a V8 engine myself years ago (in my younger days) so it's not beyond me and if it is only the head, cylinders and perhaps pistons that need to come off. Besides it is good experience for my son to learn, that way he might take better care of the boat when he takes it out.

The last few night have been lightening storms to start the motro outside, so I will probably wait closer to the weekend to do the prop, do the compression test then pull the top off the motor if necessary. I will keep you informed.

 

[Hollymax0428]

The other thing I have been thinking, with the Rotary Valve, could there be something in the timing that is not opening and closing the inlet/outlet ports in the correct position that would also affect the compression, or would the motor just not run correctly?
The idling is smooth and the 5000 rpm smooth, but the 2000-4000 rpm is rough.

 

[seadooya]

Max...by chance, you remeber cleaning the RAVES and did you notice if they were slotted? If not, that just might be the problem...

 

[Hollymax0428]

Hello Seadooya, yes they had 2 slots in each RAV. I'm pretty sure they are up the right way, but I'm going to take them out again at the weekend with the waterbox one and just check them and the bellows to make sure all is OK there.

 

[Dr Honda]

a bad, or misaligned rotary valve will keep an engine from running properly. But you should still sill see good compression numbers on a static test. At cranking speed... it can get the air needed from the exh port. But... if you are taking the engine apart... pull the intake, and check the valve for excessive clearance.

If you think the gauge may not be right... just hook it to an air compressor and check it.

A change (or lack of change) on the second test, won't give you any indication of how the bottom of the engine is. The only way you can test the bottom seals is with a leak down test.

 

[Hollymax0428]

Ok that makes sense with the Rotary Valve.

Actually I'm hoping the Compression Guage isn't right, but I will check it for peace of mind.

I've been assured the motor was completely rebuilt, so at this stage until I can get the cylinder off (if it comes to that) I'll concentrate on the top of the motor.

So low compression can only be cylinder, piston, rings, or gaskets?

 

[Dr Honda]

So low compression can only be cylinder, piston, rings, or gaskets?

on a 2-stroke... more or less... yes.

I was just thinking... did you ever go out, and pull up the choke a little while running at full throttle? I know carbs that aren't working proper may only give you a 5000 rpm topend. pulling the choke will get you that little extra full to get more RPM's out of it. (this is assuming your gauge is wrong)

 

[Hollymax0428]

Yes, I tried that. As soon as I pulled up the choke it started to die down.

With the help you have given me, as well as others, I looks like there are 2 main reasons for the revs only going to 5000 rpm most of the time.

The 2nd hand impeller I put on to test was too high in pitch, so the new one (if it ever gets here!!) should get over some of that problem.

The motor isn't developing enough hp to push the prop/boat.

I was wondering if the rings can gum in against the pistons if they have been sitting for a while. I know years ago on 4 stroke motors if they had been sitting around for a while pouring diesel down the carby while the revs were up would loosen them (and produce a lot of black smoke).
The thing we noticed when the boat was 1st put on the water that the was a lot of smoke (to the point that some on the bank thought it was on fire) coming from the back of the boat, which after a while, maybe about 3-5 minutes reduced down to the normal.
2nd time on the water 1st run for the day was fairly normal again, but it makes me think that something had been poured down the bores, or perhaps there was extra oil there somewhere.

Going to pull off the pump today ready for the new impeller and do some checking of other things that have been suggested.

I will probably wait till I get a chance to try the new prop so I don't change too many things at once, but then I will take the head and cylinders off if I don't get any satisfaction.
At the worst it is only time and a top end gasket set.

 

[Dr Honda]

It is highly unlikely that the rings would gum up. First of all... the engine is suppose to be fresh... so it shouldn't have enough time to build carbon that is damaging. Second... on a 4-stroke... the oil in the crank case can make varnish, and sludge if the maintenance isn't followed. (2-strokes don't have that) What I think is wrong, is along those lines... keep reading.

With as low as your compression is... I would be looking into that first. Even if you put in a new, lower pitch impeller... your engine still isn't running right, and may last for only a short time. If you have a catastrophic failure... it will cost a lot more than swapping the rings. (and possibly the pistons) I personally wouldn't keep running it until it was looked at.

I know you don't want to hear that... and you keep looking for some other issue... but that fact is, a seadoo 2-stoke should have better than 140 psi cold cyl pressure if it has a fresh top-end.

I have a gut felling that the engine was run hot, and/or run out of oil. When that happened, the piston crown's melted slightly, and the melted aluminum covered the rings, and may be keeping them from sealing.

 

[Dr Honda]

I just re-read your last post... Now I'm really going to say... you do not have a fresh engine. The excessive smoke is coming from inner crank seals that are bad. If it has been sitting for a year or so... you will have enough leakage to make heavy smoke (2-stroke oil is leaking into engine from the rotary valve gears)... but after that blows out... it should be fine, even if it has been sitting for a month or 2.

Unfortunatly... to replace the seals requires a crank rebuild.

Pull the jugs, and look inside. You can have it apart in 20 or 30 minutes.

 

[Hollymax0428]

Thanks Tony, it only blew the smoke for the 1st few minutes the 1st time we put it on the water. Since then it hasn’t blown the smoke again (other than the two stroke smoke).

Anyway I decided to take your advice and pull the motor down. You were quite right about the condition of the motor.
Pulled the head off and saw a problem straight away. A great heap of beach sand in the water jackets!!!

Pulled off the cylinders and the piston on the MAG end is very scarred on the exhaust side, and the bore in the same area isn't smooth.

The PTO end piston & cylinder didn’t have any marks but seeing as how only the Head and a little bit down from the top of each of the cylinders were being cooled it’s pretty obvious that at a minimum it will need new pistons, rings and if there is enough metal left, bore out the cylinders.

The beach sand was even packed right along the hose that runs between the bottom of the cylinders and looks like a fair way along the drain hose.

I’m not happy but on the upside, other than learning a bit more about the boat, it does look like the motor had been reconditioned, so I’m hoping the bottom end is still OK. I can still see the cross hatching on parts of the bore even without cleaning them down properly yet.

I've only used it the 2 times in fresh water so I can't get the blame for packing it with sand, & I’m really surprised that the previous owner didn’t notice this (I expect he will be paying for the repairs so it wouldn’t be any advantage to hide it), also I’m really surprised there is no filter on the pump inlet hose to catch sand. It is really coarse beach sand and wouldn’t need much of a filter to catch it.

 

[Dr Honda]

Thanks Tony,

I've only used it the 2 times in fresh water so I can't get the blame for packing it with sand, & I’m really surprised that the previous owner didn’t notice this (I expect he will be paying for the repairs so it wouldn’t be any advantage to hide it), also I’m really surprised there is no filter on the pump inlet hose to catch sand. It is really coarse beach sand and wouldn’t need much of a filter to catch it.

OK... so they may have told you the truth about being rebuilt... but I will say this... they most certainly new about the overheating. They may not have known why... but they knew.

I've seen this more than once... and here's how the story goes....

***them*** Hi Guys, I have a Challenger that I just had the engine rebuilt, but on the 5th or 6th trip out... all the sudden, it lost power, and there was a beeping sound coming from the helm.

***US*** Beeping... you overheated the engine.

***THEM*** Dam! I'm tired of this boat, and putting money into it!! I'm selling it!


Spin the clock about a month...


***New Them*** I got a boat, but seems to be lacking power.......


Sorry for what you found, but at least you opened it up before roasting the engine totally. Right now, you can clean the sand out of the engine, and all the cooling lines. Send the jugs out and have them bored to the next size, and get a top end kit. (pistons, rings, and gaskets)

 

[Hollymax0428]

Took the cylinders into get them checked to see what size pistons I would need, and they only need the 1st oversize -: on a recent rebuild??

Bore must have only been honed out (unless they had the liners replaced!), but when I came to order the new pistons I read out the No. stamped on top of the pistons 010-817 STD, the guy said, can't be they are out of a 720 engine!!!, and that I needed 010-857 for a 787 engine & now with .010 oversize.

I haven't measured the clearance between the good cylinder (or at least the better of the 2) and the piston but it seems to have a lot of clearance for the .006 wear limit. (.015 at least after measuring it.)
No scratch marks on this piston or bore, and I wouldn't have thought even running hot the bore or the piston would have changed sizes this quick, just the rings, but I'm not sure.

 

[Hollymax0428]

'Break-in' period for a top end rebuild

I have read quite a few suggestions on the 'Break-in' period for a top end rebuild.
Most go with in the 1st hour not opening up more than 4000-5000 and varying the revs slowly. Extra oil in the fuel as a premix along with the oil injected normally.

Some suggest other than the 1st 10-15 minutes (which is very short) to others saying 1st 10 hours (which seems a long time).

 

[Dr Honda]

Everyone has their own break in procedure. SeaDoo recommends adding oil to the first tank. (make it 50:1) that... and the injection will get you closer to 32:1 at the engine.

I'm the kind of guy who breaks engines in hard to seat the rings.

My suggestion is to add the oil, and run the boat, and have fun. Just don't hold it wide open for a long time.

I'll have to check the part numbers on the pistions... but if it was a std bore... I would say it wasn't rebuilt. Trust me... if they replaced the jugs... they would have told you. At best, they threw in some new rings to patch a problem.

 

[Dr Honda]

the number above is for a 720. The 800 engine would be a 10-818.

Well... the 720 and the 800 are both 82mm bores, but the wrist pin is a different hight. That would explain the excessive low compression... but I would think a 720 piston on a 800 crank would crash into the crank shaft. (don't know... never checked)

I really hope you didn't pay too much for that boat.

 

[Hollymax0428]

Ok thats sounds good with the extra oil & driving under those conditions.
The head bolts are fairly low torque in tightening, do they need rechecking after the 1st run?

Yes I was thinking the same about the pistons. The new ones arrived this morning & they are the same dia, same spacing from the top to the rings, but the correct ones are longer by about 1/4" and have a 3/4" hole on the side of the piston, just under the rings opposite the Exhaust side (I think from memory). Not sure what the hole does.

Definitely was 0.15 clearance between the old piston & good cylinder.
I've told the previous owner & he is going to talk to the mechanic/1st owner and get some answers.
My guess one of them had it running on the beach, filled up the cylinder journals with sand and cooked the motor, becuase the motor definitely didn't go for us right from the start. I'm probably lucky, the damage could have been worse. You were right I was looking for a different answer, but now I'm glad I took your advise and pulled down the motor.

Thanks again for your help.

Any other tips I need to know putting the motor back together. I have the Seadoo Manual which seems to cover most of it, but any extra help wouldn't go astray.

 

[Hollymax0428]

Good result

OK, just thought I would let everyone know, put the engine back together with cylinders bored out to .010 over & new pistons rings etc. yesterday & took the boat out in the late afternoon.

Went very well. 2 people in the boat without pushing it very much, got up to 30 mph within seconds and for brief moments opening the throttle got up to 40 mph & a couple of runs to 45 mph very quickly, and quite easily revved to 6500 - 6800 when needed (and once I got up the nerve to open it up a bit - didn't want the motor to blow up 1st time out ).

Didn't measure up the old pistons to the new ones exactly but just pushed both pistons over the same connecting rod, and the 720 piston is very similar but has a shorter crown from the connecting rod, so Tony, correct again there is no way the compression could be high with those old pistons. Difference is approx 1/8". Even doing a compression test with new pistons installed on a cold motor gave nearly 150 psi.

Also the new impeller on a new wear ring gives it the extra performance I was hoping to see.

Only thing now to concentrate on is the rough motor running in the 2000-4000 rpm range. Before and after that runs smooth. Maybe they run a bit rough in that range?

Thanks again Tony and everyone else that contributed. I would have given up on getting it going without your time & help. :hurray:

 

[crisso]

G'Day Hollymax
Mate.not sure what part of Oz you are in but there is a guy at the Gold Coast that is very good.He knows the in's and out's of a ducks bum.He is the chief mech. at Jet Ski World.Name is Danny.They are a Kwaka dealer but he did his time with seadoo and now works on all makes.No. is 0755379 290.Before anyone says don't go to a dealer,is a lot harder to source parts and good mechanics in Oz.This guy is from the old school.Hope this helps

 

[seadoosnipe]

A couple things...

G'Day Hollymax
Mate.not sure what part of Oz you are in but there is a guy at the Gold Coast that is very good.He knows the in's and out's of a ducks bum.He is the chief mech. at Jet Ski World.Name is Danny.They are a Kwaka dealer but he did his time with seadoo and now works on all makes.No. is 0755379 290.Before anyone says don't go to a dealer,is a lot harder to source parts and good mechanics in Oz.This guy is from the old school.Hope this helps

First, I really don't want to work into this thread. You've got a couple of the forums most experienced mechanics helping you out. At times, they may seem to give you a lot of info to digest but from what I'm reading, they are really trying to touch bases with everything that could be creating the conditions your having. Now, in the last couple posts, it seems your well on your way to having fun.

Seadooya made the comment some posts back about your RPM's not being dictated by your impeller, then as I got closer to the end, he seemed to add that it could. This is what I was looking for; that and then the fact you stated you were not running the original impeller. The RPM's can be changed if your running a impeller with to great a pitch. The motor doesn't have the torque to turn it up to it's max engine speed. I've had this occur to me personally when I was going from the OEM to a Solas Concord.

Second, ...... Dealerships? Stay away for as long as you can! Do not seek out a dealership until you've exhausted all your resources. Especially in Australia. I've had some friends from our forum there, tell me many horror stories. Basically because your on an island where they know your at their mercy. We actually have a sister parts store there, in Queensland. Their link is www.jetskiparts.com.au. I've had a couple members say they've had a hard time getting through. I tried too and it seems their server has maxed out for their bandwith. This is common for a business who doesn't normally see a lot of internet business and then, once exposed, they have to increase their bandwith. That costs more money, so if they are still building their site up, it'll be a bit before they can catch up. I haven't spoken to him in a while but the contact there is a gentleman named John Daily. If you get hold of him, he'll help you on any parts you need. But, from what I'm reading, you've got all that taken care of.

Crisso might be on the up and up with this dealership but in the past, my experience is that someone who works with or owns these sites, usually sign into the forum to plug their business. I'm not saying Crisso is doing this but it is a possibility.

Crisso... We're not totally agains't a good dealership, though good ones are few and far between. But, we are a forum where members come in to learn about fixing the problems with their ski/boats themselves. You'll rarely hear one of our members suggesting that it be taken to a dealer. Your intentions may be honest but if we (forum members/mechanics) can help this guy fix it himself (which it seems he's just about finished), then he can save major bucks. With the worlds economy in the toilet, I think that saved money might be better spent on the gas he's gonna need to put it back on the water.........:cheers:

 

[seadoosnipe]

Thanks to all.....

I believe thanks to all who has helped the member get his Challenger back up to par are in order.

Dr. Honda and Seadooya, your constant and dedicated help with this member is what allowed him to get to where he is now. At one point, I thought he was going to let it intimidate him but you guys kept him going. Now, it looks like he's back on the water.......


Thanks again to the both of you. Great job. I'm sure he appreciates all your hard work in helping him get it going again. You both know as well as I do, that work would have cost him a few thousand if a dealer got involved. So, :cheers: to the both of you!!!!!!!!......

 

[Dr Honda]

Hollymax... I'm glad it's up and running. but knowing that someone who was suppose to be a "professional" mechanic installed the wrong pistions... I would look into legal action to recoup some of the $$$ back. (if you have something on the original sale papers saying it was rebuilt)

Snipe... Thanks for the pat on the back. Nice to know I'm liked. :cheers:

To all... this is an excellent example of why you should always try to do your own work. Over the years, I have found that many of the people who become mechanics are half retarded... and go to a local tech school because they can't do anything else in life. the majority of them work at car dealerships, but a few find their way into the powersports industry. So... on top of shoddy work... you pay a premium for labor.

This is not a bash on all mechanics... I'm just saying to know who is working on your stuff.

Because of what I said above, is exactly why I get my hands dirty on a daily basis. I have BS degrees in Physics and Biology... an AA in Liberal Arts, and a Math minor with the Physics. I turn a wrench because I want to... an not because I have to!!!

(sorry, but it really pisses me off when a so called professional does something as stupid as using the wrong pistons, and calls it a rebuild. at best, with the proper pistons, I call it a freshening up)

 

[seadooya]

To all... this is an excellent example of why you should always try to do your own work. Over the years, I have found that many of the people who become mechanics are half retarded... and go to a local tech school because they can't do anything else in life. the majority of them work at car dealerships, but a few find their way into the powersports industry. So... on top of shoddy work... you pay a premium for labor.


)

Yeah, you go ahead and hire all the "non-techs" for your "motorsports" facility, to do your services. Atleast, the ones w/ the certs, have a reason for the schooling, they have passion for what they do.

 

[seadooya]

I believe thanks to all who has helped the member get his Challenger back up to par are in order.

Dr. Honda and Seadooya, your constant and dedicated help with this member is what allowed him to get to where he is now. At one point, I thought he was going to let it intimidate him but you guys kept him going. Now, it looks like he's back on the water.......


Thanks again to the both of you. Great job. I'm sure he appreciates all your hard work in helping him get it going again. You both know as well as I do, that work would have cost him a few thousand if a dealer got involved. So, :cheers: to the both of you!!!!!!!!......

Appreciate the shout-out, Snipe....:cheers: