1991 yamaha 225TXRP will either stall during acceleration or run like a dream

johncheng

Cadet
Joined
Dec 29, 2011
Messages
8
finally got the boat out after a long summer of replacing stringers and deck.

i have a 1991 2.6L yamaha 225 txrp that was sitting for 5 years, after a little work it starts and idles at 800 rpm and can raise idle no problem in neutral. when i shift into gear and attempt to accelerate it seems to bogg down and stall out. 1 out of 10 attempts to it will take off and run fine up to full throttle and runs great as long as the rpm is kept above 1500rpm, if it drops below that it will sputter and stall out most times.

I have replaced both fuel pumps, plugs, t-stats, fuel seperator, fuel tank, all lines, prime bulb, water pump, lower unit oil and completely cleaned carbs for the first time according to manual. i did not attempt to adjust floats in carb as i didn't have measuring tool at time of disassembly and reassembly. i did notice that pilot screw were out 2.5 turns before disassembly although manual outlines 3/4-1 1/4 turns out. i have also checked compression in all cylinders and they are good.


i'm leaning to toward doing the carbs again, any suggestions would be appriciated.
 

RAGO53

Recruit
Joined
Sep 16, 2012
Messages
2
Re: 1991 yamaha 225TXRP will either stall during acceleration or run like a dream

I have had a similar problem with my 250 HP. (My engine has 3 fuel pumps so double check yours to make sure you only have 2.) I've had all the pumps changed and change the plugs & filters every season.

My problem tends to occur in hot weather. Starts right up. Idles fine. Goes at full speed fine. I get to my destination and sit for a few hours. When I go to leave the engine is warm so the cold idle does not kick in and the engine only idles at 600 RPM's. It stutters and dies when I put it in gear or it knocks as if skipping a cylinder when tolling slowly and eventually stalls. This is exacerbated if I had the engine trimmed up. I have to quickly get the throttle up to 1,000 RPM's in gear after I start it or it will stall.

The on the spot solution is to press the neutral switch on the throttle so I can rev up the engine to a couple of thousand RPM's for about 30 seconds to a minute. Then I put it back down to normal position, put it in gear and can usually get up to speed with only occaisional stalling. Once I get to normal operating speed (4200 RPMS) it runs great and won't stall at low idle as long as I have run it at 4,000 RPM's for a few minutes.

So, I'm baffled. I am suspecting it is either, carbs that need to be cleaned or an electrical sensor somewhere that is affected by hot temperature. Why it corrects itself after I run it at 4,000 RPM's for a while is the puzzler.

I'm going to get my carbs cleaned when I winterize the boat and hope that solves it.
 

johncheng

Cadet
Joined
Dec 29, 2011
Messages
8
Re: 1991 yamaha 225TXRP will either stall during acceleration or run like a dream

Yamaha is running great, so i removed the carbs last weekend and cleaned up all the passages again. i look through the old post and found that there is an additional fuel pump, prime start pump, so i took that apart as well. i didn't find any tears or hole in it so i just cleaned it up and put it back together. i believe the problem was the floats in the carbs. they were all equally off by about 13mm, so i set them up and resync. everything and it ran great.
just wondering if anyone would know why they would set the floats lower then spec but have the pilot screws out twice the spec. i know for a fact the the motor was running before it sat for 6 years.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
8,851
Re: 1991 yamaha 225TXRP will either stall during acceleration or run like a dream

I do not see how the float setting would effect the idle of a motor.

Apparently the pilot/idle jets/passages were plugging and someone decided to try to put more fuel into motor to try and make it idle.
 

RAGO53

Recruit
Joined
Sep 16, 2012
Messages
2
Re: 1991 yamaha 225TXRP will either stall during acceleration or run like a dream

I do not see how the float setting would effect the idle of a motor.

Apparently the pilot/idle jets/passages were plugging and someone decided to try to put more fuel into motor to try and make it idle.

I just got my 250 serviced and they found one float needle was bad. They replaced it.....cleaned the carbs and the engine is running great. Suddenly getting 5700 RPM's. I was topping out at 5100-5200 before. Appears to have solved the problem.
 
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