1999 yamaha waverunner 1200xl purchase

[NIL8er]

wrong thread

 

[NIL8er]

Don't want to frighten you but I have many years experience with these engines both regionally racing and bone stock recreation. Souns like you are lightly seizing one cylinder. This. Will manifest itself exactly as you describe. While I have personally seen many different reasons for this, by far the number one reason was a crank that had twisted a few degrees out of index. In effect this advances the timing in that cylinder causing it to overheat and lightly seize. Cools off and starts but will continue to do this until the repeated light seizures reduce compression and begins to be a very noticeable power deficit.

so do you know if its necessary to rejet with the cat removal and d-plate & chip in place???

 

[Ubiquity]

so do you know if its necessary to rejet with the cat removal and d-plate & chip in place???

On my stock rec boat stock jetting was fine as long as the airbox and waterbox had not been modified.

 

[NIL8er]

On my stock rec boat stock jetting was fine as long as the airbox and waterbox had not been modified.

thanx.................:thumbsup:

 

[NIL8er]

Judy posting common possibilities based on my experiences. Have you checked the one way vent valve for the tank? Air should pass into the tank but not out.

how hard should it be to blow into the vent valve ? should it be free flowing or some resistance. im getting resistance but can still blow through it .

 

[Ubiquity]

how hard should it be to blow into the vent valve ? should it be free flowing or some resistance. im getting resistance but can still blow through it .

.

If the gas cap is on you will feel some resistance since the tank will actually pressurize. Take the gas cap off and you should be able to blow through with little/no restriction.

 

[NIL8er]

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If the gas cap is on you will feel some resistance since the tank will actually pressurize. Take the gas cap off and you should be able to blow through with little/no restriction.

i had the the valve off altogether and it was definitely not without resistance, i would say on a scale of 1-10 it was a 5 in difficulty to blow through. But it should be say as easy as blowing through a straw?

 

[Ubiquity]

i had the the valve off altogether and it was definitely not without resistance, i would say on a scale of 1-10 it was a 5 in difficulty to blow through. But it should be say as easy as blowing through a straw?

To eliminate the valve just replace it temporarily with the correct size vacuum hose barb fitting. Don't do anything that will vent tank to engine compartment!!!!! If your boat has a fuel delivery problem severe enough to shut it off your likely causing seizure type damage. I know you think im the grim reaper but ive been in denial before myself lol still betting your lightly seizing one cylinder because your crank is slightly out of index.

 

[NIL8er]

To eliminate the valve just replace it temporarily with the correct size vacuum hose barb fitting. Don't do anything that will vent tank to engine compartment!!!!! If your boat has a fuel delivery problem severe enough to shut it off your likely causing seizure type damage. I know you think im the grim reaper but ive been in denial before myself lol still betting your lightly seizing one cylinder because your crank is slightly out of index.

As I previously said its not shutting off. Does not heat up. Compression is even in all three cylinders. I rebuilt the carbs and its gotten better but still is lean with idle to mid speed but over 15 mph its fine. Needs slight choke until 15 mpd then no choke . it'll run pretty well at lower speeds without choke but I can tell it's not quite right, but is better with a little choke. I prob need to adjust low speed carb adjustment.