Yamaha 30hp Need Help With Idle Running Away?

HI,
I am new here and was hoping some one could help. I have or what i am told i have, is a split year motor its a yamaha 30 ELG from japan? 1988 1/2 but i am having a problem with the idle running away. Just rebuilt carbs and tune up now when you fire it off and shut the choke off the motor just idles all the way up cranks herself out...... any ideas or possible answers??

Re: Yamaha 30hp Need Help With Idle Running Away?

ok lets review the ways we can increase RPM in any given range by a few hundred RPM.
one is advnce ign timing, check the timer base for correct position and ign timing.
the second is to increase both air and fuel in the correct ratio.
double check your linkage sychronization and throttle shutter settings. now would be a good time to recheck your link and sync.
according to your model number you have a 3cyl oil injected 1988 yamaha.
no split years until after the 06 model production run.

Re: Yamaha 30hp Need Help With Idle Running Away?

from your PM, and I rarely rarely answer technical questions via PM's, you dont have a service manual.
get one before you tear something up.
ya gotta remember when that motor was produced, 1987-2002, I was playing on Gray boats for the USN as a Firecontrolman.
I dont see enough tiny mites here to remember the procedure to correctly set the oil pump link rod, carb shutters,timing pick up and idle timing.
its in the service manual though and I have done it I just wont attempt it from memory and a keyboard.
done correctly and the ign system is working properly and the fuel system,including the fuel pump is in good condition that 3cyl motor ran very well.
you also may wish to tune up the cooling system to include the water pump kit and a T-stat.
have you tested the compression? thats first on the list for any tune up or service.