Motor Won't Start

A few days ago I picked up a 12 tin skiff - older MirroCraft - for a very good price, knowing that it's a fixer-upper. Got lots done to the boat/trailer and it's ready for the water. When I looked at it, the guy told me he'd installed a carb kit in the motor and put in a new impeller, since it'd been sitting for some years. Motor is a '91 Force 15 hp.

When I looked at it, he had the motor running and tho' it sounded a little ragged it seemed responsive enuf. I found that the trailer wheel bearings were bad, so he went to pick up new ones and I worked at fixing those for a couple of hours. Tried the motor again and it started right up.

OK, it's been sitting for a week or so, then yesterday I dropped it into a nearby canal and tried to start it. No luck.

(I ran a chainsaw in the Idaho woods, falling timber for years and have a technique developed for starting 2 stroke motors that haven't been run for a bit. Ignition on, choke out, (butterfly closed) hold full throttle and crank it several times till it sputters, then open the choke (butterfly open) give it full throttle and crank it. Boom....running)

I tried that with this one and had gas everywhere. Motor flooded instantly. Finally gave up and tilted the motor to load boat back on trailer and gas started pouring out of the housing. Whoops - unhooked the gas line very quickly.

Got it home and pulled the plugs and yup, dripping with gas. Cleaned and dried the plugs, cranked it a dozen times with plugs out to dry the cylinders a bit, then put the plugs back in and tried it again. Nothing. Checked plugs and they were dry. Couldn't get that thing to leak gas again, tho' carb looks wet.

Went to parts house and picked up an inline spark plug tester and had no spark. Traced that to shorted kill switch and now had spark showing. I've cranked that thing with and without choke till my arms are sore and can't get a pop out of it. Plugs are still dry, even with choke closed, so I assume something not opening in carb. Had the fuel pump off and it looks good.

This thing is new to me, Idaho was 40 years ago and I've forgotten a lot. What should I look for ??

Sorry to hear of your problem.

I had bought a 18 hp 'rudeon which the PO had rebuilt the carb. He left out the little wire retainer for the float needle & the needle was jammed open, flooding the motor.

Your description sounds like a stuck open float to me. You might want to pull the bowl off & check it.

Good luck.

If the float is stuck then the carb will overflow as you pump the primer, which would never get firm. If it is firm, then the needle is working, or there is a bad blockage in the carb. On a functioning system, the primer will get firm when the carb is full and the needle closes off the passage, and stay that way as long as the engine is running.

Chances are there was junk in the carb bowl, and it has now sucked some up and plugged the jets. It'll need to be taken off and gone through. You can also give it a little prime of premix, carb cleaner, whatever down the throat, see if it pops, to confirm that it is lacking fuel.

If your spark tester is one of those with the little light bulb, it is next to useless for actually troubleshooting spark. You need an adjustable gap inline tester, to verify that the spark is actually hot enough to fire under compression, in which the resistance is much higher than at atmospheric pressure.

I'd also confirm that you have the right plug and right gap, as plugs are the 1st thing I look at for hard starting. With that said, the Force CDI units can be brutal ... intermittent ... as in one day they work and the next day they won't :shock: . I finally gave up on the 15hp one I had, it was just too unreliable. And even worse, even a new replacement $350 CDI would likely be suspect too ...

As above, checking and cleaning your ground on the coil is free and easy.

While you have it off test it and check it for cracks.