1996 Yamaha Waveraider Stumbles at 1/4 Throttle

johnkom

Petty Officer 2nd Class
Joined
Jul 26, 2004
Messages
163
Starts and runs great. But when you hammer it, it only goes 1/4 rpm or so and stumbles sometimes dies. If you crack the chock one third when it stumbles it accelerates to full throttle. Push the chock in and it continues to run fine at full throttle. It has been sitting for two seasons without use. However new plugs and fresh gas. Where do I start? Or just run the **** out of it for a while hopping it comes out of it.

JK
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,310
Almost certainly I’d be looking at the condition of the accelerator fuel pump or carbs in general.
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,310
There's an accelerator pump???

Yeah. Not sure what you guys over there call it...but both carbs have this type of fuel induction system. Often when they are weak or perished...some guys try to compensate by fitting primer pumps. This is to overcome the real issue of this or the check valve from the tank failing. Or both.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,993
My Mercruiser 3.0 liter did not like to be hammered. I went thru 3 accelerator pumps (internal carb part) before I got one to work. Back in the late '80s they apparently had issues with replacement parts. I realize this is a Yami, but the result is the same.

Using a choke to get a weedwacker to run full speed is often a problem after a few years. The tiny jets need to be cleaned and re-adjusted.

In nay event, you got a carb problem.
 

johnkom

Petty Officer 2nd Class
Joined
Jul 26, 2004
Messages
163
"In nay event, you got a carb problem."

Agreed. Looks like a winter project. Too many other thinks to do it this season yet. Thanks for the input.

JK
 

JerryTX

Cadet
Joined
Oct 1, 2012
Messages
7
I have a '94 WaveRaider and had the same issue. The fix was cleaning the carbs and new spark plugs. It isn't a hard procedure to do.

When you run it last at the end of the season be sure to run some fuel stabilizer through the system and that will help next season.
 

johnkom

Petty Officer 2nd Class
Joined
Jul 26, 2004
Messages
163
FYI: Rebuilt carbs, synced and set up to specs. Runs like a scalded ape now!

JK
 
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