78 Evinrude 150 Problems

Well I was in a Bass tournament out on a local lake, had just rebuilt the carbs on the engine and it was running good once it fires up and stays running. Well around 10:30 I'm cruising down the lake with my partner, running good, and then it cuts down to about half power, comes off plane, and does about 10mph... I shut if off thinking maybe my throttle linkage came unbuttoned or something, pull the cover and its fine. Try to re-fire the engine and it'll fire on one cylinder, the starter disengages, and the compression of the next cylinder stops the engine and doesn't fire... After just about killing my battery I said the heck with it and threw the trolling motor in the water and used that to get back to the state launch. Left my weigh in sheet on the presidents truck and left. Of course, then coming home I have the rear wheel bearing blow out a mile from home... Nursed it back to the driveway and there she sits...

I'm thinking one of the power packs (CDI box, whatever you want to call it) burned up and isn't sending spark to one bank of cylinders. Does it make sense to everyone else?

Re: 78 Evinrude 150 Problems

Nobody?

Re: 78 Evinrude 150 Problems

did it overheat?

maybe the kill switch fell out? i'd say no though because it kepy going then died. just a thought though.

does it have spark now after you've let the motor cool down?

Re: 78 Evinrude 150 Problems

It is possible you got a powerhead overheat and the horn did not sound. Pistons can swell when overheated and cause that type of running scenario you mentioned. Do a compression check. If the compression is stopping rotation of the engine, it is also possible you have a hydraulic lock, possibly from an internal water leak. Pull the plugs and crank it. See what comes out of the spark plug holes. Put an inductive timing light on each plugwire when you crank it and see what the flashes in the gun tell you. Is the spark intermittent, no spark or weak? Which ones spark? Make sure the link arm from the spark advance lever to the timer base did not come undone.

Re: 78 Evinrude 150 Problems

Alright, I am literally just getting around to fixing this thing. The motor is not locked up, I could always turn it over. I looked at it today and I can't get a spark out of it whatsoever. Now, my spark tester busted (tried it on a lawnmower that runs and didn't do a thing), so I put a plug on a wire, held it tight to the block and looked for a spark... Nothing, from either bank of cylinders. Where do I start? I was supposed to take it out next week but not if it won't start...

Re: 78 Evinrude 150 Problems

I'd start at a compression test before I did anything else. Post those numbers, then pickup another spark tester.

Re: 78 Evinrude 150 Problems

It's unlikely all 6 coils went at once. Also, unlikely both power packs went out at the same time. That leaves the stator or the timer base. I'd check them first. An inductive timing light is helpful to show spark quality on each plugwire.

Re: 78 Evinrude 150 Problems

I know the compression is low on all 6 cylinders. High 80's if I remember right. That's not the issue though. The spark is. The thing will run with low compression, sure its low on HP but all I need it for is tooling around the lake, I'm not racing it. The timing light is a great idea, but I don't have one in my arsenal... I'm a diesel guy, ignition systems are a whole other world to me. I could pick one up, but honestly if I'm not seeing any spark with a plug pressed to the block what would a timing light tell me? I've read that its possible the key switch is grounded out, and therefore grounding out the ignition. I'm gonna pull that apart and check it today. If not, is it really worth putting a new stator into a motor that needs to be rebuilt anyway? I could probably get $150 at least just out of scrap for the darn thing, better off buying another outboard.

Re: 78 Evinrude 150 Problems

If the compression's that low, unless I was ready to tear it down and rebuild it top to bottom, I wouldn't spend a lot of money on it. No since putting a band aid on a mortal wound.

Re: 78 Evinrude 150 Problems

The compression on that engine when new was probably in the 110+ range. At 80 lbs, you are well below the 10% variance allowed. I'd recheck it first.