Logo
FULL SITE MENU

F25 (mfg 2000) stalls on accel

R

ram95

New member
I've got a 2000 F25 that stumbles or quits when advancing the throttle. I've pulled the carb off and cleaned the pilot jet #50 and the main jet #108 and the internals and put it in an ultra sonic cleaner at 140 degrees for 45 minutes. Still does the same thing.

Starts great and idles great. NO water in the fuel. Fuel pump works good.

If I put it in gear and quickly open the throttle while holding three fingers over the air intake it winds right up. If I don't put my fingers over the intake it falls on its nose and quits.

Any ideas. New carb? This thing is a real challenge.
 
ram95 said:
If I put it in gear and quickly open the throttle while holding three fingers over the air intake it winds right up. If I don't put my fingers over the intake it falls on its nose and quits.
Click to expand...

Citing your statement above...when you cover the air intake you richen the mix (more fuel, less air), and the motor responds. I'm not familiar with your carb, but I recon it should have a idle mix screw. This screw has a specific "turn out" spec. This spec is found in your service manual.

With the engine off, turn in the screw gently until it seats. Note the number of turns. Let's say it took 1 full turn in to seat. Then turn out the screw 3/4. Start engine and see how it responds. The more you turn in the screw the more you richen the mix. Just like putting your hand over the intake, except more precise of course. Make your adjustments to the idle mix screw small, 1/4 turns at a time.
 
You're correct. However, this carb does not have a mixture screw. But, thank you for sharing in my (misery) frustration. At least the carb is easy to remove and disassemble. I have some jet reamers and reamed out the pilot jet which did seem to improve things a tad, without upsetting starting or idle. So now, I will remove the carb once again. This time I will pressurize the float bowl with a squeeze bulb and actuate the throttle accel pump and try to see where it squirts fuel (if it squirts fuel.. which I assume it should) since I previously cleaned everything and the little piston & ck balls seem free.
 
You'll definitely want to be able to see through each jet after cleaning. Doesn't take much debris to clog their orifice.
 
Yeah, I'm aware of that one. Like I said, I disassembled this thing completely, including the top plate which has the little brass oriface that can easily be lost, and I put the whole works in the ultra-sonic cleaner. I think the problem is in the "acceleration circuit" somehow. So its coming back apart today and I will put fuel to the float bowl and holding the carb level, I will work the arm on the carb to activate the accel pump and see if I can see what happens. To me, it should squirt some fuel into the venturi area. I'll post the result.
 
If you still have the problems after your attempt the best advice I can give you is to register on this forum: http://www.yamahaoutboardparts.com

Start a new thread that includes the engines complete model number and year. Detail the problem along with everything you've done. Pictures help too. There are master yamaha mechanics on that forum who can help you troubleshoot.
 
Back
Top