johnson and evinrude

[Russell Holland]

1985 johnson 235 ran good. Ran a couple of weeks ago on the muffs no problem. Tried to start again and it started and ran for a second or two. Now it only spins over and backfires ocassionly.I have tried spraying 50:1 mixture into carbs,And it looks like the primer is working. It backfires through the exhaust only.Ihave not checked to see if plugs were firing. If it was powerpak, I wouldn't think both were out ,should get some want to start.Is there somthing to cause no fire to the entire engine,and produce back firing symptoms beside the timing off or a broken key.It rained alot the last month, woul water in the fuel cause near shotgun backfires.If you put #1 piston tdc and the timing marks somewhat line up,could you assume the flywheel key was ok. Would a slight bend of the key cause the timing to get off enough to cause this.I guess I need to look for fire and bad gas.All plug wires are correct. Wont try to start at all, just backfire but not always.Plugs looked like the were gettin fuel.thanks for any help.

 

[dajohnson53]

Re: johnson and evinrude

I had that same powerhead and vintage (early 80s J235). Had a similar problem and it turned out the key was broken. I don't know how the mechanic diagnosed it - whether it was outright obvious or whether he had to pull it or what. All I know is it was acting like your describing, at least superficially, he replaced the key and it worked.

 

[rickdb1boat]

Re: johnson and evinrude

Run off a portable tank mixed with fresh fuel and oil mix to eliminate that as a problem. Sounds like you have spark if it's backfiring, but check all the plugs for spark anyway. It is possible that you sheared the key, but if you check the timing, that will tell the story on that. You are on the right track in your thinking. Make sure the timer plate under the flywheel is not sticking and advancing the timing at idle. At TDC, you should see the timing retarded slightly(4-6 Degrees) if correct or near to correct.

 

[JB]

Re: johnson and evinrude

Moving to J&E Troubles