1995 150 Looper Stalls When Given Throttle

[s.wxman]

Hello to all,
Try to make a long story short. Engine ran fine for years with basic maintenance. Started having issue where it would just cut out (stop), instantly, when underway. Very intermittent, but it was like someone pulled the emergency stop when it happened.
First Evinrude certified mech said it needed two carbs rebuilt and that it had wrong plugs. Didn't make it across the lake before issue happened again.
Second Evinrude certified mech said all carbs needed rebuilt, even the two what were just done, and replaced the primer bulb, which was only a few months old. Also said wrong plugs installed and went back to plugs first mech said were wrong. Issue was not fixed and boat just didn't want to run correctly.

I got two manuals, OEM and Clymer, and decided the pack was bad. Replaced pack and optical sensor (CDI parts). Put in QL78YC plugs. The original issue of cutting out when underway appears to be fixed.

Boat starts fine first start of day. Quickstart SLOW system all appears to be working correctly as does the shift interrupt. Runs well out on the water and idles right where it should.

Problem is after first start of day. If I sit and fish a while and go to move, the motor will start fine and go to idle after a few seconds just like it should. But, it dies when I put it in gear, or, it may continue running, rough, at idle then die when I try to advance the throttle. May take four or five starts to get underway and I will often have to just slam it into gear and go to half throttle or so all at once to get going. Once past this and finally underway it runs fine again. Throttle movements while underway don't cause any coughing, missing etc., smooth back and forth just like it should run. I can go to idle, or neutral, and then advance into gear and get underway again without issue as long as I don't stop engine and let it sit for any amount of time.

I am convinced the electronics are fine and this is some kind of carb adjustment or fuel problem, but I am certainly not a pro or even too experienced. I am hesitant to go back to the local mechs because of such poor troubleshooting on the original issue. None of this existed before, only the instant "off" while underway, which seems to be fixed with the new pack.

Looking for suggestions where to start. Thanks

 

[s.wxman]

Re: 1995 150 Looper Stalls When Given Throttle

For anyone interested. I "think" I may have found the problem. It will be a couple days before I can get on the water to confirm.
Reading over Link/sync procedure in manual it looked like something I could do a sanity check on since I thought this was fuel related. Just looking for something obvious.
The very last section concerned 'fuel/spark synchronization' I think it was called. Anyway, when advancing the throttle the procedure said to verify that the carb linkage to open butterflies and the timing lever (a wheel attached to throttle shaft pushes against this lever to advance timing) began to move at the same time. Mine didn't. The carb linkage was activated quite a bit before the timing was being advanced. I tried to follow procedure to change and ended up moving the adjustment from about 25% to the right of the slot to about 75%, or about half of the total available adjustment. Visually, the carb linkage and the timing lever appear to begin movement at the same time now. It responds better to throttle on the muffs. I hope for the same on water.

Made a little sense to me sense once I could get in running at higher throttle positions, it seemed fine. This hopefully correlated to the timing eventually reaching max advance and it was running right. It was only at the very low throttle settings where the carbs were too open for the amount timing advance I was having problem. Cold starts just a fluke that the extra richness didn't kill motor.
Really anxious to get it on the water.
Does this make some sense to anyone else? I will be tickled if one screw fixed this problem.