Force Outboard Sputtering

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gogittum

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I'm having fits with a 1991 Force 15 hp outboard on a 12 ft tin boat. When I got the boat, I had to use ether to get it started. (I know, I know, ether is bad) It leaked gas and when tilted gas poured out of carburetor. Previous owner says he put in a kit, but I doubt it.

I pulled the carb and disassembled it, then soaked it overnight in carb cleaner. Used soft copper wire to clean the jets, etc., blew it out with compressed air, set float level and re-installed it.

Still needed ether to get it going the next day, but once started then shut off, it would re-start easily. It doesn't pour gas when tilted anymore.

I put the boat into a local canal, started it and moved out into the channel, then hit the gas. The motor took off strong and smooth and the boat came quickly onto plane - for 100 yards, then the motor quit. It seemed to me later with motor on the muff that a piece of grit must've gotten into a jet, so tore it apart and went thru it again, but this time put a big fuel filter on it.

Now, I did get it started when cold one time with choke and no ether. Put it in canal yesterday and it idled fine, but popping now and then. When I hit the gas, it started to go, then sputtered - more like cutting out - then go again, then cut out....kept me about 1/2 way on plane. rrrrrr-p-p-p-rrrrrr-p-p-p, etc. After a bit it suddenly cleared its' throat and took off. WOW. I screamed down that canal on full, flat plane at about 20 mph - for about 200 yards, then it started cutting out again. It did get me back to the launch, but it was a bit tense.

I put in a fuel pump kit and noted the inline filter on pump output. It seemed clean and fine.

When I got it home, I checked spark plugs, spark plug wires, the wires coming from under flywheel and all seem tight and secure, tho' the insulators on the flywheel wires are torn up where they plug onto the coils. Spark plugs look new. Started it on the muff and it seems to run "fairly" well, but idle mixture screw has very little effect, so I suspect an air leak, but used a thin layer of permatex on carb gaskets and all is clean, tight, sealed and new. I deeply hope it isn't a crankshaft seal. In spite of that, it does idle fine.....with some popping.

It still pops at idle and cuts out at higher rpm - air leak shouldn't cause that. I took a short video of it -
https://youtu.be/QVQqJtiCW3o

I'm a better than fair mechanic, but 2 strokes are mostly outside of my experience area. Can anyone give me an insight of what to look for on this thing ?? I'm about to tear my hair out.
 

MrGiggles

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I noticed in the video that you squeezed the primer, do you need to do that to keep it running? If so, that is your problem, fuel pump is not working properly.

It should not stay hard while running, but if you prime it up and leave for a couple minutes, it should stay hard.

Any air leaks in the suction side, be it the line, primer, fuel pickup in the tank, whatever, will cause it to not pump well if at all.
 

gogittum

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Thanks for the reply. No, don't need to squeeze bulb to keep it going, but bulb was hard when I started and after it had run for a few minutes, I checked it and bulb was soft. As you can see in the video, it didn't seem to make any difference when I squeezed it - ran more poorly, if anything.

In my experience, a motor starving for fuel has a certain characteristic. Hit the gas and it kinda sits there and goes, gaaaahh, gaaaahhh, then catches up. This is a definite cutting out. I tried to get video on the canal but nearly went for a swim, trying to hold camera, steer the boat, balance me, etc., but it was a sharp, definite cut-out, like a switch being turned off and on. You can hear that in the video, too.

I know absolutely zero about these ignition systems. Only thing I can see that's bad are the plastic boots that cover the connections where wires from under the flywheel connect to the 2 ignition modules/coils. The actual connections are tight and clean.
 

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