older johnson 40 hp. need help

[perchmaster]

hi, so i love to fish and finally had enough money saved up to buy a boat. my first for sure. well i end up spending around a thousand dollars for a refinish 14t fiberglass boat with a motor. the motor started from day one, but when it was in gear and i throttled up it would kick out of gear. well i took it in and the guy said the lower was shot. i saved some more money and he fixed it. i was so excited. i took my new fiance out to show her my bill dance skills and it ran great. for about 15 min. then at full throttle my speed just shut down to and idle. it would start and go into gear but would not accelerate fully. so once again i took the motor back to the mechanic. he sold me a carb rebuild kit, and new points. so i put the points in and did the carb thing. took it out again and it ran like a dream. i was so happy. finally i got a dependable boat i could fish out of. well thats what i thought! about a week later i took my buddy out from out of town and the damn thing would not start. so my question is...what could be wrong now? i check the points again and they seem well, the carb seems good, spark plugs are fine. i just dont get it. i know im not the best mechanic but just dont know what to do. almost have an additional 600 bucks into it and it wont run..please help. i dont have the money to fix it now. maybe spring. so any ideas would be greatly appreciated. im pretty disapointed. fish to be caught and no boat. thank you.

[budnate]

pull both plug ground on the block and you have bright blue spark at both plugs, right?

check compression at both holes with both plugs pulled

double check you points and make sure ther nuts on .020 gap and report back.

[AuroraDan]

Perch,

Had similar weird problems with my 1957 18 hp Evinrude. Was out with the wife crabbing in Tillamook bay and I started to loose power, acted like lack of fuel problem. Even after grabbing the primer bulb (I had changed to a single fuel line and modern tank) and pumping it hard no change. Limped back to the dock with about 25% of full power.

Quick check when back home, found I had spark on one cylinder only. About five months prior I replaced all the ignition parts, thinking something I did came apart I tore her apart. All was fine but noticed a light film of oil all around the ignition componants. Looked closely at the crankcase oil seal and sure enough it had torn and was letting fuel/oil mixture coat everything and prevent the ignition parts from making good electrical contact. Before I replaced the seal I wanted to see that the oil contamination was the problem. Unbolted all the ignition parts and cleaned with a can of carb cleaner. After reassembly pulled the starter cord and she roared back to life.

With a new crankcase oil seal, that motor worked flawlessly for many years. It's actally still here, been replaced with a 15hp Honda. Cannot bring myself to sell her ;-)

Anyway, check to see if you have good spark on both cylinders, you are welcome to PM me if you have any other questions.

Dan

[Lou]

I had a simular prpblem with a 57. Turned out to be the woodruff key.
It was distorted, just enough to prevent running. In the long run, the
crank actuallt bent!
I run Mercs now.