30h Stutter on Pickup

[JackHunter]

im hoping that someone can help me out

i have a 2006 Yamaha 30hmh and it is stuttering as i open the throttle up (about 1/3) as soon as im on the plane it has no issues all the way to WOT

I have Cleaned the entire fuel system from Tank to Carb (including the Carb), Replace the plugs and checked spark

 

[99yam40]

Re: 30h Stutter on Pickup

have you checked for fuel pump leaking into crank case?

Maybe you just have not followed the link and sync procedure after reinstalling the carbs after cleaning.

I am guessing this motor is a 3 cylinder and has 3 carbs as there has not been a 30 2 stroke here in the US for many years so not sure what that motor has

 

[JackHunter]

Re: 30h Stutter on Pickup

From what i am finding i dont think it was released in the US, its a 2 cyl single carb 2 stroke

 

[99yam40]

Re: 30h Stutter on Pickup

well that rules out syncing the carbs:lol:

Too rich or too lean of a fuel to air mix will not let a cylinder fire properly.

All you can do is eliminate other things and then look for fuel problem if nothing can be found wrong with spark, timing, and compression.

timing light might show a loss of spark at certain RPMs on the different plug wires
But monitoring the voltages would be better
In to and out of CDI and out of secondary of coils to plugs if you can find the proper test equipment

 

[JackHunter]

Re: 30h Stutter on Pickup

Tested the spark system according to the manual and it is within specs.....

i did go back and look at the fuel pump and when i squeeze hard on the primer bulb i get very small drip from the rear diaphram (never thought to prime it hard before now) so i am thinking that it might be sucking some air under load ?? i have ordered a new pump it will be here tommorow hopefully that is all it needs