88ish 100hp 4 cly. johsno problems

[bcfrizzell]

Hello, I got a 88 Baja Sport 164 with a lunker of a 2stroke. When It runs good it rips *** with all the goodies i put on. Problem is when i open it up and take a corner(motor calls for more power) it dies on me. Its almost like any excessive stress on the motor will stall it.
I changed the fuel fliter, fresh gas with some gas treatment stuff... didn't work. I thinks its probly carb problems now that i fixed the fuel... but what should I do?

 

[DJ]

Re: 88ish 100hp 4 cly. johsno problems

Built in fuel tank?

When you say "take a corner" how far is the boat leaning?

 

[emdsapmgr]

Re: 88ish 100hp 4 cly. johsno problems

Possible it is running out of fuel in the corners. Are the floats set properly in the carbs?

 

[bcfrizzell]

Re: 88ish 100hp 4 cly. johsno problems

hey its a built in tank. I changed the fuel filter, ran it and found a slight problem. I took out the spark plugs to find a small hole at the top of the piston. I assume its running to hot. I havnt had time to change the plugs but what should I do. If i fix the problem causing that cylinder to run hot, do you think it will be alright to run it? The whole is small and is only about a fingernail deep.

thanks

 

[emdsapmgr]

Re: 88ish 100hp 4 cly. johsno problems

Not sure just what your definition of a "small hole" is. Is it a dent on the piston top, or does the hole go all the way through the piston? I'd pull that head off and have a look. Post some pictures. Best to have a look now. If you continue to run the engine, the piston could disintegrate at any time, causing a catastrophic (expensive) failure. You may be looking at a complete teardown and overhaul.

 

[bcfrizzell]

Re: 88ish 100hp 4 cly. johsno problems

the hole it about the thickness of you fingernail deep, and bout the thickness of the led on a pencil. But no, the whole has not gone all the way through. There are also some metal fragments on the spark plug obviously. I have cheep walmart oil in is now (oil injected) that im going to take out and put in good stuff. that being said do you think if i fix the problem like change the plugs or whatever, can i get away with running the engine with the slight "dent" in piston?

 

[emdsapmgr]

Re: 88ish 100hp 4 cly. johsno problems

It is not unusual for a crossflow engine to eat a piston ring when the engine gets high hours on it. When the ring becomes damaged, it will usually catch on one of the intake/exhaust ports-causing the ring to break into pieces. These pieces typically will wind up in the combustion area and will get pounded between the surface of the head and the top of the piston. You may be seeing these "dents" in the top of the piston. While the engine may run, that cylinder will usually be low on compression. You will want to pull the head on that side and perform an inspection.

 

[bcfrizzell]

Re: 88ish 100hp 4 cly. johsno problems

That could very well be the problem. But i seem to think that the carbs dirty and probably sticking and running that cylinder lean causing that hot spot and the whole. I wouldn't call it a dent, if you look at it close up you can tell its from high heat burning a hole in it. Imm gunna clean the carbs and such, but is their anything else i can do befor i start buying top end parts?

 

[emdsapmgr]

Re: 88ish 100hp 4 cly. johsno problems

Yes, it could very well be a lean situation caused by a carb with restricted fuel passages or blocked jets. You can pull that carb apart and check that side of the carb which feeds that cylinder. If you ever plan to fix the engine, you will have to remedy the cause of the failure anyway. Pull all the jets and look for restrictions. Also- could be from too much timing advance. Check the sync and link and put a timing light on #1 and #2 to double check where the full advance timing is set.