Old issue with 1991 Force 35 - Fuel issue after an hour

[Evinrude_NooB]

I'm still having a fuel issue with a Force 35 and it's baffling me.

When it's cold, it runs really well after it starts up.

About an hour after running, it seems to be fuel starve. Initially I thought it might be because the engine wasn't getting enough cooling and fuel was evaporating in the carb. So today I ran it with the cover off. Sure enough, after an hour, it started idling rough and stalling.

I felt the carb and the motor with my bare hands. It was cool so I'm ruling out fuel evaporating in the carb. However, I do notice that there isn't much fuel being delivered. Meaning, there's usually some fuel at the butterfly value if I rev the motor a little bit on neutral, but that was not the case after running an hour.

So it appears to be a fuel starvation issue, but what is causing it? And why does it happening after about an hour of running?

Any opinions and/or suggestions would be much appreciated.

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

Adding some additional details:

* The bulb is firm
* It stalls at idle
* Doesn't want to restart

 

[jerryjerry05]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

What kind of tank?
6gal or built in?
A slow die can be a clogged vent?
Try checking the diaphragm or valves in the pump.

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

it's a 6 gallon tank.

I'll take the fuel pump apart and check everything again. I'll include pictures. It's really bugging me because I can't seem to find what the heck is causing it and it's consistent. About an hour after running, it bogs down. My initial thought is some kind of expansion that's causing the issue with the fuel pump itself.

 

[jerryjerry05]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

Replace the hose and squeezie.
Then drain tank.
Pull the pickup and see if it has anything blocking it?
Does it squeezie hard again after it's stalled?
No wanting to restart, could be the seat in the carb is swelling(really reaching out there)or the floats not set right?

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

It does squeeze hard after it stalls and you got me thinking, Jerry. You think it may be the carb float? Maybe it's a really-really slow leak and it takes an hour for the float to fill? Grasping at anything at this point. I'd taken the fuel pump apart previously and noticed nothing obviously wrong with it. Same with the carb. Nothing really stood out.

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

I have my old 1987 Force 50 that's been sitting around waiting for a piston/ring replacement. I wonder if the carb from that will fit only the 1991 Force 35. IF that fits, it could be a quick test. Well, not that quick since I have to take it out and run it.

 

[jerryjerry05]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

Probably won't fit.
What float do you have?
Foam or metal?
Metal,take it out and stick it in a glass cup of 50-1 gas.
Check for bubbles?

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

Neither foam or metal float. It's plastic.

I did the float test and there doesn't to be any leak(s) in the float after letting it sit for an hour. I decided to leave it there overnight to see what happens. The carb actually looks fine.

I have a 3 gallon tank I'm using for tiller. I'm going to switch the tank, hose, and primer bulb over and see what happens. Hopefully I can try it this Sunday.

Any other suggestions I can try before that?

 

[jerryjerry05]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

The white floats.Junk.
Post a pic.
Every time I try to use them I end up putting the original back in.

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

Check the float this morning after it's been sitting in the drink over night and it seems to be ok. Meaning, it was floating and no leaks detected. Probably was white at one point but now it's sort of brown/red color.

I'll snap a picture of it tonight after work and post it.

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

If the float was leaking and sinks, wouldn't that cause a flooding condition, and not a fuel starve condition? In that case, wouldn't there be lots of fuel be leaking out of the carb?

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

Well, the float test passed. Even after 'floating' for 24 hours, it was still floating normally. Although 1/2 the gas in the container had evaporated. I put the carb back together and on the motor. I guess the next test will rely on the 2nd gas can, primer, and fuel line. Hopefully will get to try that out this Sunday.

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

I must have the worst luck.

Changed fuel line to 5/8", bulb, and tank. Took it out to the lake today and it ran great for a 10-15 minute ride WOT. Turn the boat around and decided to make another run. Five minutes into the 2nd run noticed smoke coming out of the cowl and engine started missing. This was the same sign I got when my first motor overheated. Immediately turn off the motor and took off the cowl. It was smoking and HOT. Paint had peeled and I was fearful the motor bit the dust.

Put the trolling motor down and slowly roamed the lake with the cowl off to cool it. After 25 minutes the motor was cool enough to touch. Decided to see if I could start it. God was smiling down on me today because after 3 cranks, it did start. Shut it down again because it looked like the impeller or the water pump bit the dust. It wasn't spitting out any water.

After I took it home, I sprayed as much Sea Foam as I could in each cylinders. Decided to do a quick compression test to see how bad it was. Had to say, I got lucky. Compression was still a respectable 100-110 psi.

So today was a bit of a disaster, but not a total disaster. Didn't get to run the motor for an hour to test out the line fuel setup. On top of that, almost fried the replacement motor for the one that was fried initially.

I'm wondering if some seaweed got into the water pump and clogged it up. There were tons of weed on the lake. Will find out when I drop the lower unit to look at it sometime this week or next weekend.

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

It seems that I've damaged the motor a bit.

When I first got the motor, compression was at 148 and 145psi.

Now it's 100 and 110psi. It does start but I'm going to lose top end power, aren't I?

What can I do, besides a piston and ring replacement, to get it back above 130psi?

 

[jerryjerry05]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

It's possible the head gasket went bad?
Get another gauge,try another test.
Spray some oil in the cylinders and see if the comp raises?
Test the same? Pull the head?
See if it's leaking between the cylinders?

Your right you do have crappy luck!!

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

It's end-of-season I might as well do some work on it. Replacing the impeller, checking the cylinders and head gasket will be easy. I sprayed a lot of Sea Foam in it yesterday. I may pull the head gasket tonight to do a physical check on that and the cylinders. Makes me want to quit boating with my luck.

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

Got ambitious tonight and decided to check the head gasket. All but one head bolts came off easily. The last one required a little extra but came out, too. The last bolt looked like it was a little fried and not nice and clean like the others so I was thinking the head gasket bit it.

I could not get the head cover off. It was stuck on pretty tight. I even put a little wooden block on it and gave it a couple of minutes of tapping and it still wouldn't come loose. Decided to put everything back together and just spray more Sea Foam in the cylinders. Took a compression test of both cylinders afterwards and got some pretty promising numbers.

Cylinder #1 was at 125#
Cylinder #2 was at 130#

Not what it was when I bought them above 140# on both but not terribly bad. It'll run.

Next task, pull the water pump and replace. Also install tell-tale. Also check why the heck the overheat buzzer did not go off.

 

[Evinrude_NooB]

Re: Old issue with 1991 Force 35 - Fuel issue after an hour

Now back this old issue.

Impeller was replaced and while I was there, I changed the L-U oil.

Took it to the small lake for a run today. But this old issue reared its head again. After it runs for a while, it doesn't want to stay running when I put it into gear from idle.

It starts and idles fine, but a little on the low side. I put it in either forward or reverse and it stalls. But it'll start again. It's frustrating. When I got home, I adjust idle up.