140 johnson no wot with cover on.

Was out over the weekend. (140 hp 1982 johnson). Boat ran like crap. Lots of misfiring and sputtering with the ocassional smooth run. I had a similar problem earlier in july and bypassed the fuel filter and it seemed to clear it up. Over the weekend I removed the motor cover to check my plug wires etc. I noticed that the engine would run much better with the cover off, but it was way to loud to enjoy boating. A couple days ago I checked my plug wires and determined that one was pooched, so that has been changed. While I was at it I changed all my fuel lines to 3/8 up from the original 5/16 lines (boat originally had an 85 Force), from some reading on the forum the suggestion it that the 140's like the larger diameter lines, and also installed new spin on fuel filter.
Today I took it out and could not get above 3000rpm. I beached and started looking at the cam follower position. I noticed that I was not getting WOT based on the position of the butterflies in the carb when the controls were pushed to the WOT spot. I adjusted the follower and WOW what a difference. The 17' foot bayliner goes like stink and has tremendous holeshot.

Re: 140 johnson no wot with cover on.

Continued...
I thought that I had it beat until I put the cover back on and once again no WOT, terrible plane time etc. I checked the movement of the timer base the best one can for interference with the cover it doesn't look anything is impeding it. It is hard to figure out. Motor runs awesome, never better, with cover off, put cover on runs terrible. Anyone know what the measurements are for the WOT stop screw position for the timer base? The manual says 3/8 to 7/16 to the front side. The question is what is the approximate measure of the length of the stop screw from the rubber stop to where it threads into the block (behind the carbs on the top of motor slightly below the flywheel. This measurement would be on the rear side of the reference point given in the Seloc
Much thanks

Re: 140 johnson no wot with cover on.

Don't trust your wot timing stop to a measurement. If you have moved it or replaced ignition components, check it with a timing light.

Those motors have a habit of shorting the #4 plug wire to the latch on the hood. Moving the wire away may help, may take a new wire. May not be the problem but it sure acts that way.

Re: 140 johnson no wot with cover on.

Wow, you got a 140hp Johnson on a 17ft Bayliner ??? What year is the Bayliner ???? and what is it's max rated HP ???
I have heard of the plug wire shorting out thing as well.

Re: 140 johnson no wot with cover on.

could you be sucking exhaust gas into the cover,through the seal?

Re: 140 johnson no wot with cover on.

Dhadley said:

Don't trust your wot timing stop to a measurement. If you have moved it or replaced ignition components, check it with a timing light.

Those motors have a habit of shorting the #4 plug wire to the latch on the hood. Moving the wire away may help, may take a new wire. May not be the problem but it sure acts that way.

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I will probably replace the other three plug wires tomorrow. Does anybody know what 4 cylinder auto make has the same coil/distributor connectors as the OMC 2 strokes. I can probably get the parts as an auto listing a lot cheaper than the $12.00 dollars a wire I paid last. The HEI chev set-up looks very similar as so does a ford 3.8l set. Can probably make two sets from auto wires for the price of one from the OMC dealer with only half the work because the plug side boot is already attached.

Re: 140 johnson no wot with cover on.

I would not use car wiring on plug wires. You need to have solid wire cores on the plug wires. If you don't want to pay for the expensive plug wires, get the wire cut from a bulk roll at your Bombardier dealer and make your own from the parts you already have. They sell it under p/n 772584.

Re: 140 johnson no wot with cover on.

emdsapmgr said:

I would not use car wiring on plug wires. You need to have solid wire cores on the plug wires. If you don't want to pay for the expensive plug wires, get the wire cut from a bulk roll at your Bombardier dealer and make your own from the parts you already have. They sell it under p/n 772584.

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I will second not using car wire.