F100 - Fuel coming out of air intake screen

[TigerMo]

On my Yamaha F100, I was running it on the ear muffs with the engine trimmed up (past the top of end of the trim indicator, but not tilted all the way up). I smelled fuel and took off the cowling. After cranking it back up, I saw fuel coming out of the bottom of the air intake screen on the front of the engine. <br /><br />Tilting the engine up made it worse, tilting it down into the trim range of the tilt/trim stopped the fuel "leak". I just had the carbs cleaned and rebuilt.<br /><br />Is this normal or is there a problem I need to have looked at?<br /><br />Thanks.

 

[rodbolt]

Re: F100 - Fuel coming out of air intake screen

Hello<br /> I dont think the needles will seal well with the carbs at that attitude. why do you trim it so much to flush it ? you will increase the risk of water ingestion from the exhaust ports running at an extreme angle. you really should operate this engine as designed. good luck and keep us posted

 

[TigerMo]

Re: F100 - Fuel coming out of air intake screen

Its hard to describe how far up the engine was trimmed, but the prop and intake were below the boat, and not at an angle where the prop would have been out of the water, even partially. I've had to tilt it that high before while fishing in shallow water on the edges of flats (and getting pushed by the current onto the flat) - just past the last "bar" on the digital trim meter.<br /><br />Is there a max tilt angle for proper operation (more specific than the obvious that I know now - don't tilt it so high that fuel leaks out of the air intake)?<br /><br />In this case, because of the ground slope under the trailer and the height of the tongue, the motor couldn't be tilted all the way down without hitting the dirt. After lowering the trailer jack, I was able to tilt the motor down further and had no more leakage.<br /><br />But since the carbs were just taken apart and cleaned I was worried there was some other problem besides operator error.

 

[rodbolt]

Re: F100 - Fuel coming out of air intake screen

hello]<br /> I am not aware of any max angle of operation. I do know that when trimming to full up sometimes a small amout of fuel may be spilled from the carbs. but the needle valve should still seal it. I will try to ask my tech rep sometime this week]<br /> did you ever run it trimmed up like this before without a problem? it is possible to have a float that drags on the bowl and does not seal. my opinion of the carb set up with the 4 strokes. all not just the yammi is not good<br /> Good luck and keep posting