Logo
FULL SITE MENU

25 Hp 2011 3C dropping bottom cylinder full throttle.

W

Westex

New member
Just got this 2011 25hp 3 cylinder and its dropping the bottom cylinder a little over half throttle. I changed plugs, added injector cleaner but it has not solved the problem. Every now and then it will pick it up for a minute the fall right back off. Spark is there checked that. Could it be a bad injector and is there a way to clean what I have? Any help is greatly appreciated.
 
Before you buy an injector, swap it. Move the bottom hole injector up to another cylinder and put that one down low. If the miss follows the injector you have your answer. If it stays on the bottom cylinder it isn't the injector, and you just saved a part.

Stuff in the tank won't clear a partly blocked one. There's a tiny filter basket in the injector inlet and it isn't serviced on the motor... the injector has to come out for an ultrasonic clean and a flow test. I've had one that looked perfect and flowed about half what the others did.

Spark there at idle doesn't mean it fires under compression at WOT. An inline spark tester on that hole while it's acting up tells you more than a plug laid on the block. I'd check compression on all three first too. A hole that's a bit low will carry at idle and drop out once you put load on it... which is just about where yours quits.

The way it picks up for a minute then falls off makes me look at the wiring as well. Wiggle that injector connector with it running. What's the exact model and serial number? I could be wrong on the layout, but the swap test works either way. Keep us posted. thanks
 
Miles2000 said:
Before you buy an injector, swap it. Move the bottom hole injector up to another cylinder and put that one down low. If the miss follows the injector you have your answer. If it stays on the bottom cylinder it isn't the injector, and you just saved a part.

Stuff in the tank won't clear a partly blocked one. There's a tiny filter basket in the injector inlet and it isn't serviced on the motor... the injector has to come out for an ultrasonic clean and a flow test. I've had one that looked perfect and flowed about half what the others did.

Spark there at idle doesn't mean it fires under compression at WOT. An inline spark tester on that hole while it's acting up tells you more than a plug laid on the block. I'd check compression on all three first too. A hole that's a bit low will carry at idle and drop out once you put load on it... which is just about where yours quits.

The way it picks up for a minute then falls off makes me look at the wiring as well. Wiggle that injector connector with it running. What's the exact model and serial number? I could be wrong on the layout, but the swap test works either way. Keep us posted. thanks
Click to expand...
Thank you for the information. The model# is 1A25413FK serial# is OR429632.
I had already ordered a new injector so I installed it and got the same dropping out at WOT but it does hold it a little longer it seems.
Compression is 135 across all 3 cylinders. I swapped coils from #2 hole to #3 hole and got same results.
I don't have the inline spark tester but I will order one today.
Is there a trigger under the fly wheel like the old two strokes that could be failing?
 
Back
Top