Carb Rebuild?

[97GTS]

Got home today and tested in compression and it was still at 120 on both cylinders and that's with open throttle but the ski started right up with new plugs and new gas (mixed 40:1) and the ski ran fine in the driveway on the hose... once I took it to the lake and put a load on the ski I could only get half throttle and the ski wouldn't rev any higher... Came home and cleaned the carb and have not tested on the lake again but the ski is like missing and or backfiring while on the hose at half or full throttle... I am going take the ski to the lake this weekend and try it again... any suggestion at this point?

Took the carb off and cleaned it (took apart) and put it back together a ran the ski in the driveway on the hose and it ran good but at half throttle or above it starts to like miss it seems like...

Should I adjust my carb or get a carb rebuild kit and go from there?

Thanks
Chris

 

[Jetskigoodies]

Sounds like you are in need of a rebuild now. Good compression is 150 for your model. on the very low end 125. You are at the kill point. If you had a 951 that would be ok. When I say rebuild I mean your whole motor, not the carbs.

 

[97GTS]

I just did new rings a couple of years ago... now thsi year I had the cylinder walls honed so could they have taken to much off while honing the cylinder walls?

 

[Jetskigoodies]

Its possible but 120 is very low compression.

 

[97GTS]

ok, ok, I take the ski to the lake what would the ski run like with low compression? cause the ski runs fine just seems like it is having trouble getting gas like a carb issue

 

[Jetskigoodies]

It will bog and hesitate, run and then die. On land it will run fine. When in the water the engine is put under load and will perform poorly.

 

[97GTS]

would the ski not do the same of it wasnt getting the right fuel ratio (premix)? and or the carb ist adjusted properly?

Just trying to figure some things out... very frustrating... lol

Chris

 

[Jetskigoodies]

You can try a different compression tester and see if you get different results. If you get better results then go through your carbs. Make sure they are dialed in correctly and do a pop off test to see if you need a rebuild on the carbs

 

[97GTS]

would the ski not do the same of it wasnt getting the right fuel ratio (premix)? and or the carb ist adjusted properly?

Just trying to figure some things out... very frustrating... lol

Chris

 

[mashenden]

Its possible but 120 is very low compression.

JSG is right - that is way low. I'd say that this is the thing to chase. No sense in chasing a carb problem when the compression test shows a problem.

 

[Bills86e]

These symptoms suggest the Rectifier is going bad and you may be getting AC current in this DC system. Replace it.

Bills86e

 

[Jetskigoodies]

These symptoms suggest the Rectifier is going bad and you may be getting AC current in this DC system. Replace it.

Bills86e

Rectifier???? His compression is 120 in each hole. He had low compression back in 6/2011. He just replaced the rings back then. That is just putting a bandaid on a flesh wound. He is lucky he got 1 1/2 more riding seasons for $40.

 

[mikidymac]

I just did new rings a couple of years ago... now thsi year I had the cylinder walls honed so could they have taken to much off while honing the cylinder walls?

Not sure why you would replace the rings a couple of years ago but hone the cylinders this year? Why would you hone the cylinder this year and not replace rings? It sounds like you need at a minimum a new top end but it depends on how many seasons the engine has on it. It sounds like you are looking for a simple fix but as others have said with your compression at 120 psi no amount of tuning is going to get your power back.

The only other thing I can think of to answer your question is that with the ski out of the water and reving it to 1/2 or full throttle could still cause the engine to hit the rev limiter because there is no resistance of the water. I have seen guys at the launch ramp run the skis and bounce them off the rev limiter just to blow the water out. Not a good idea but this is probably the miss that you are refering to.

 

[anthonygrato]

would the ski not do the same of it wasnt getting the right fuel ratio (premix)? and or the carb ist adjusted properly?

Just trying to figure some things out... very frustrating... lol

Chris

Do you run premix with the oil still hooked up or do u have block off plates installed?

 

[97GTS]

I have a block off plate installed... and also I did hone the cylinders when I replaced the rings a couple of seasons ago... when I replaced the rings I was getting between 140 and 145 compression and this least season a couple of bolts broke on my exhaust manifold so I had to take the cylinders off to repair them... while I had them off I honed them again and one I replaced them I tested the compression and I am now getting 120 on both cylinders... The only thing I can think of is that the person who honed them might have honed to much (Is this possible?) If not then I am going to have to do a top end rebuild... The engine has 380 hours on it


Chris

 

[LouDoo]

Just my 2 cents, take it for what it's worth, probably 2 cents. Your motor is done, 120psi and 380 hours is about all you can expect. I would recommend getting a rebuild while you still have a re-buildable core, or just run it until it quits and part it out.

Your just wasting your money with a top end rebuild, your engine is tired.

Lou