acceleration problem

[lajones]

I have in 1993 Tigershark Daytona 650. At the end of last season I began to have an acceleration problem that goes like this. At a complete acceleration the jet ski jumps forward as it gains RPMS. Half way through the throttle up the engine seems to bog. At that point you can move the throttle up and down in the high range with no response. But if I hold the throttle full or three quarters open and I hit a wave the jet ski will engage a run like a bat out of hell. As long as I keep the throttle in the ¾ and up the ski runs very well after the engine engages. I have put a complete rebuild kit on the carb. Installed two new spark plugs, but no change in the above symptom. Could weak reed valve or valves cause this type of symptom? I’m Puzzled. Can anybody help me along with this? Thanks lajones

[Bryan Glynn]

What is your compression? No a reed would not do that.

[lajones]

Thanks alot for a very quick response.

I just took the compression and both cylinders measured 140 psi.

[Bryan Glynn]

OK...did it do this before you rebuilt the carb? If no, I'd say something went wrong there.

[titanic]

Sounds like fried pistons and/or head gasket to me.

[lajones]

The symptom is what prompted me to rebuild the carb. I thought their might be some trash (lack of a better word) floating around blocking some jets or channels in the fuel manifold. Do you think this is a carburation concern rather than a some sort of electrical concern -- ?

[Bryan Glynn]

It sounds carb related to me - perhaps something was missed during the rebuild...

[lajones]

The one procedure that I did not performed during the carb rebuild was checking the pop off pressure, could this be a possibility in the symptom that I have described.

[Bryan Glynn]

Did you check the Needle and Seats?

[lajones]

Bryan, I checked the needles and they did not appear to be scored in anyway. So I did not attemp to remove them. I just shot carb cleaner through the seats. Can the low and high needle seats be removed ? I removed and clean the low and high speed jets under the fuel manifold but not the needle seats. You think this was a mistake ?

[Bryan Glynn]

I don't know what you are reffering to - you mean the adjustment needles? Yes you should have removed them, cleaned out he passageway and replaced the o-rings.

[lajones]

Yes, I did remove the high-speed and low speed adjustment needles and cleaned out the passages. My question is can the high speed and low speed needle seats be remove?

Again I want to thank you for your time in answering my questions in this frustrating matter a hand. I just know it must be something simple I have missed.

[Bryan Glynn]

No, they do not come out.

[lajones]

Then if the seat is scored and it can not be removed, then is it time for a new carb? If this is the case do you guys sell them?

[Bryan Glynn]

It's part of your carb body, and yes if the body is damaged it's time for a new one. No we don't sell them - try Bill at www.watercraftmagic.com