Yamaha 150 2-stroke stumbles then ok

louiefl

Petty Officer 2nd Class
Joined
Apr 11, 2012
Messages
119
[FONT=&quot]Yamaha 150TXRB 2-stroke carbed starts and idles fine, but bogs down going through a range of about 1500-2200. It doesn't like sitting at that range at all if trying to troll. Push through it and the engine runs cleanly with zero issues all the way up to 5000 rpm. From idle doing a fast hole shot there aren't any issues, but barely can sense that hesitation going through that range. Fresh gas. Could this be something in one of the carbs? Timing? [/FONT]
 

louiefl

Petty Officer 2nd Class
Joined
Apr 11, 2012
Messages
119
A couple weeks ago I decided to tear apart the carbs and found a couple partially blocked jets, the floats were too high, grooves in a couple needle valves and the pilot screws were adjusted too far out. Could have done it without a rebuild kit except for the needle valves so it's peace of mind that I used them. I've rebuilt a few carbs before and these were pretty easy. Boat idles smoother and no more hesitation mid range. Before I was topped out at 42 mph and now hit 48 mph at 5200 rpm and could probably hit 50. The real test was about 15 mph, bow high just off plane, before there is no way it would have sat there and now it hums along like it should. Should have done it months ago, but was worried I'd screw something up, no issues.
 

robert graham

Admiral
Joined
Apr 16, 2009
Messages
6,908
Install fuel/water seperater filter on transom, use Stabil or similar all the time, drain carb float chambers a couple of times per year or for extended motor lay-ups....these will eliminate most fuel related issues....
 
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