[Brew]

My '86 Evinrude 140 runs great for the first 10-15 minutes we are on the lake. After this, it stalls upon acceleration. It seems to idle ok, and runs great if you can get it up to speed, but getting it there is difficult.It is definitely a fuel problem as I've discovered that if I hold in the choke as I accelerate, I can prevent the stall (although it still isn't a smooth acceleration).I've cleaned the carbs (replaced gaskets, needle valves/seats) ensured the intermediate air bleeds (jets?) are per the manual and replaced the fuel filter. When filling the gas tank, some excess gas came out of the vent, so I assume it is not blocked.I tried pumping the gas line bulb while accelerating, but this seems to have no effect. The bulb does go a little softer than the firmness achieved when you initially pump it, but it is not totally deflated.Any thoughts on what I can try next?As always, many thanks to those who take the time to read our endless problems and provide suggestions.Cheers.

[ebbtide176]

hey brew, have you ckd out the other forum called "Merc bogs on accel then fixes itself"?? i can't offer any tips, but i've just recently put your same motor on my boat so i'll keep an eye out for your posts

[Brew]

Hi Ebbtide..Thanks for pointing out that other post. I had read it, but unfortunately I've already de-carbed motor, cleaned carbs, and I don't think I can adjust the idle as carb jets are fixed and not adjustable (short of replacing the jet).Since you've got the same motor on your boat, other items of interest that have happened on my motor are: Gasket between the two halves of the block gave up. You'll discover this one if A: you don't start, and B: you see small gas bubbles coming out of the seam on the block. Nasty repair as it involves taking much of the motor apart.Another interesting item are the tubes running between the carb barrel and the carb float chamber. They were made from some wonky plastic that disentigrates over time. I didn't have any success in getting replacement tubes from Evinrude (they want you to buy entire carb), so I just went to a hose supply store and found something that worked.Good luck with your beast. Nice to know someone with same motor to bounce ideas off of.Cheers.

[sho305]

I had a primer bulb go bad and restrict fuel. Try releasing the motor end fitting with it off the motor so you can pump fuel out of it. Or take a carb line off and it should pump out good. Tank pickup can get clogged too, or fuel pump may be bad. My bad bulb filled pump and filters with rubber chunks. Make sure you are not overheating or such, I just looked at a cooked 140 with the thermostats melted down into the heads from a bad impellor. I would also check your plugs to see if one is different than the others, and look for a heat related problem maybe. If a plug is very light colored that would be lean and can cause damage. Normally if a tank restriction the bulb will go flat. Check pumps/filters. Otherwise it looks like a low speed circuit problem in the carbs, but that would be apparent all the time not just hot, and you may have multiple carbs. May be an ignition thing, some Mercs have a low and high winding in the stator (+/- 3000rpm about)and what ever one goes out will screw up the ignition at that speed. Hope this helps.