Re: Top speed with 18hp Evinrude on 14′ aluminum

[stephenspann27]

I was trying to spare you all the saga. I’ll try to keep it as concise as possible. I bought the motor 1965 18hp evinrude not running. It had been sitting a long time and it had belonged to the sellers deceased father. The seller said it needed a new coil. The first thing I did was order a coil and rebuild the carb. The lead plugs were missing from the carb, and I replaced those as well. For some, still unknown reason, I could never get the float needle to seat properly, I tried several different needles, different seats, different floats etc, but the thing would squirt fuel when the bulb was pumped.
I finally gave up on that carb and bought one off ebay. The seller had listed it wrong and sent me a much larger carb than what an 18hp uses. I filed out the manifold holes and made the carb work. With this carb installed I got the engine running for the first time but it had a severe missfire.
I bought yet another 18hp carb, and this time I received the correct part.
Back to the missifre, I replaced both coils, installed new points, condensers etc. I set the points via feeler gauge, then fine tuned them using an ohm meter. The missifre was still there. One constant problem I had was the flywheel rubbing the coils. I had the coils as far inboard as they would go and they still rubbed the flywheel. I started to be convinced the flywheel was bent, or the crank was bent, or the crankshaft bearings were bad. The flywheel did have a little bit of run out.
Since I was desperate to make progress I ended up buying a whole new powerhead. I put that powerhead on, and still had the missfire. At this point the only part of the ignition system I hadn’t replaced was the plug wires. The wires ohm’d out fine, and I had freshly terminated them. In another act of desperation I ordered a new flywheel, and the mag plate, coils and the whole shebang from the same seller who sold me the powerhead. I was also tired of fighting problems with my rope recoil (even after replacing the spring) so I ordered another one of those. Finally with all these new parts the motor seemed to run great. Nothing was left of the old setup from the midsection down. I think the missfire was probably from bad plug wires all along.