Rebuilt 1 engine, the other engine blows!

[geoffw]

If you follow my last thread, I bought my 95 Speedster last month for $800 and did a full rebuild on the starboard engine (new crank and top end). I also rebuilt all 4 carbs. The boat was running REALLY F'ING GREAT for 3 days (3-5hrs max).

Then all of a sudden, Iam on plane at 1/2 throttle and the port engine shuts off. It started back up but wouldnt run. I immediately knew what went wrong so I pulled the head and low and behold the same cylinder with a hole in the piston at the SAME EXACT spot as the starboard engine.

Keep in mind, this engine had perfect 145psi compression and freshly rebuilt carbs, Sea-Doo mineral oil and fresh plugs....It makes NO sense why it would just go lean and crap out all of a sudden.

I think its time to look for an I/O boat. These carb'd 2-strokes just dont cut it in the reliability dept for me.

Anyone have a similar issue with random MAG cylinder lean out and melt down ? Anyone know of a cause?

-Geoff

 

[Gamerse]

Try reading this thread, it has pictures, so maybe it is a similar problem.

http://www.seadooforum.com/showthre...Hole-In-PTO-Piston&highlight=lean+hole+piston

:cheers:
Ernest

 

[parrothd]

When you cleaned the carbs did you replace/clean out the fuel selector switch and replace the fuel lines? Probably ran the first and then the second engine lean..

 

[BMANN06]

Same thing happened to me couple years back. If your buying a two stroke pwc/boat (10+yrs old) be it a seadoo or any other mfg. And the engines haven't been rebuilt. You can basically count on having to replace them. I learned the hard way as you did ... as many members have too. FWIW ... once you get them in ... get your carbs sorted ... your good to go. It's not like they blow every couple years.

 

[Sink]

Sounds like you are going to have it all redone and be ready to go for years! Getting something else just gives you the chance of starting over with someone else's problems. Boats are money pits. No matter what you go with, you have to maintain them. It's not like a car... Good luck with whatever you do.

 

[geoffw]

No, I didnt even think to check the fuel selector switch. Ill pull the carb apart and see if the fuel filter is clogged up again.

On another note, if I repair this engine, how long do these things typically last? Am I looking at a reliable boat for another 2-3 years or do these things go out every year?

The one engine I rebuilt is running great.

-Geoff

 

[ocod]

No, I didnt even think to check the fuel selector switch. Ill pull the carb apart and see if the fuel filter is clogged up again.

On another note, if I repair this engine, how long do these things typically last? Am I looking at a reliable boat for another 2-3 years or do these things go out every year?

The one engine I rebuilt is running great.

-Geoff

depends on you.
you can make engine bullet proof but if there is a weak link in the fuel/air that will cause problems.
Maintenance is key

 

[Sink]

Use the right oil, do the maintenance, it will last many years. It's a 95. Do you know if it's been rebuilt before??? 16 year old boat needs some TLC!

 

[parrothd]

I have the original engines from 1998 in my boat, just need to do all the maintenance, including checking the fuel and oil systems yearly and fog after every use..I'd check that the switch isn't plugged up and for air leaks, they both can cause lean seazure ...

 

[roneagan@cfl.rr.com]

My 98 still has the original engines and runs great.. They last a long time if you take care of them, I am thinking about rebuilding mine this winter, I think it may be time..

 

[Comp]

Does your boat have grey fuel lines on it? If so you need to change them all out or you will just continue to have fuel system problems. Couple of months back I purchased two 96 GTX skis with 787 engines in them. Both had engine failures on the PTO piston and both were damaged on the same day. The owner said something about it being an additive he put in the gas. I knew this couldnt be the case otherwise both pistons would be melted, not just the PTO.

Both skis still had the grey fuel lines which I suspected to be the problem. This was verified when I went through the carbs and found the filters in both PTO carbs were completely plugged full of garbage from the fuel lines. I basically bought 1 top end kit plus another gasket kit and carb rebuild kits for both skis. I replaced the burned pistons, rings on both pistons and rebuilt the carbs. I got the first ski running last week and tested it and runs great. I currently have the 2nd ski about 3/4 back together and should be able to test it soon also.

I would suggest getting another fuel filter and put it in the line just before the carbs to catch anything else that may possibly get through. Those filters in the carb are pretty small and it wouldnt take much to plug them up and burn another piston.

 

[howie099]

Hole is piston is coused by heat and lean fuel mixture. Could of had an airleak somehwere eles also or just a clogged fuel fitler. I would say the air leak could be in the top end since the plug burned the hole in the piston. I usually set the carbs a little rich. Plugs are cheaper than engines. I would think if you still had the injection system the oil would be enough to cool the piston also since you here only 1/2 throttle. If you still had some fuel getting in. Last time I burnt a piston my mixute was lean and I was using premix. Looking at the plugs is the best. They should look like a nice brown color on the insulator.

 

[El Toro 33809]

It is my understanding the it is the fuel that cools the engine and the oil that lubricates it.