1999 speedster, full throttle hesitation

[Stacy]

Rev limiter??

 

[howie099]

It is sounding like the accelerator pumps. You can try them anywhere just move the levers and you can hear or watch the gas squirt in the carb when you move the sticks. It might take a few mins after the rebuild to fill up the lines again but after than it should be fine. If you replace them with tygon or clear you can see the fuel in them.

Also you put in new needle valves and seats? Those are extra from the standard kits. I would put the carbs all back to stock and go from there.

 

[robomatic12]

I didn't put in new needles and seats purely because they are expensive! What size tygon are the lines? Is it the same size as the oil injection lines?

 

[howie099]

I know the needles and seats aren't that cheap, but you need them sometimes. They are about $15 a carb not all that bad. You can get a good aftermarket carb kit and needle & seat for $50 each or about $15 more for Mikuni kit. On that old of the boat should of put new needle and seat since they are more than likley OEM.

Every carb I do I put the needle & seat and never had an issue with them after the rebuild. You could be leaking fuel from the needles.

I think the lines where 1/8 or 3/16.

 

[robomatic12]

So I swapped out all of the pop-off springs for the original 30-32psi springs. I checked the operation of accelerator pumps, they were squirting in gas correctly. I used new carb base gaskets.

The boat runs much better and the problem is almost gone but still there if I'm fast on the throttle. I'm going to change the fuel filters to see if it helps. I have the low speed needles set to 1.5 turns out and high speed at 0 turns out as per fsm.

Anything else to check? Earlier it was suggested a leaking exhaust might be it, how do I check this?

 

[Renehasp]

Did the fuel filters help?

 

[robomatic12]

Nope, but for future reference I used the napa gold ones with a metal casing. Worked great.

I ended up buying OEM mikuni carb rebuild kits, set the pop-off too 38psi. The Winderosa gaskets had corroded and pretty much turned into garbage. Also put new OEM needle/seat and OEM accelerator pump gaskets. Boat runs perfect now.

Lesson learned, don't cheap out on rebuild kits!!!