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76' Evinrude 15hp running issues/?'s

TylerC

New member
Ive got a 76 evinrude 15hp, model 15604A. Got my water pump issue fixed finally. Seemed to run pretty good in the barrel. I know the carb needs cleaned/rebuilt for sure as I bought this motor last year and did not get to run it at all until this week. So on to my questions.

Took it out on the river this evening and it definitely was not revving high at all. If I had to guess I'd say we were 5 mph maybe a touch more. But definitely lacking for sure. Im going to find someone this winter to do a full over haul on the motor but for now I'd love to be able to take my boy out a few more times before we run out of good days. I ordered a carb kit. Are there any other places you would check first that can cause my issue? Gonna slap a couple new spark plugs in as well. Basically just looking for any quick area to check/repair/replace to get some last few days of the season in.
 
Does the manual fuel pump go hard when you operate it ?---Post the actual compression values.-----Does spark jump a gap of 5/16" on both leads?----Use a spark test device for that test.----Sounds like it is running on 1 cylinder.
 
Does the manual fuel pump go hard when you operate it ?---Post the actual compression values.-----Does spark jump a gap of 5/16" on both leads?----Use a spark test device for that test.----Sounds like it is running on 1 cylinder.
Yes the manual fuel pump stays hard when its running. I'll bring it in to work with me today and use snag my brothers testers and see what it does.
I was just thinking about it, when I had the motor running in the barrel after replacing the water pump, it ran a lot stronger than it did last night out on the river. Don't know if that helps to point to anything or not.
 
In a barrel there is lots of air / exhaust in the water.----This makes for less load on the motor.---It then sounds more powerful to you.----Do some testing to find the issues.
 
In a barrel there is lots of air / exhaust in the water.----This makes for less load on the motor.---It then sounds more powerful to you.----Do some testing to find the issues.
Makes sense. Ill test those few things today and post my results! Thanks
 
I didn't get a chance to check compression, but my brother took a second ro check it out with me today. The plugs looked good and were gapped at 029 I believe. When we were checking spark, one had a weaker spark and the other was good. We got looking at the electrical plug on the coil and pulled up a diagram and we're pretty sure they were hooked up backwards so we swapped them and it fired up first try and very strong. Tried it again a little bit ago when I got home and fired first try and nice and strong and sounded much much better than it did yesterday. Planning on going out Saturday morning to do some fishing so that'll be the real test.

I do still plan on testing compression, just ran out of time today. And speaking of them being plugged in backwards, just to make sure we were right, can you tell me for sure which plug/coil is supposed to be one and two?
 
If plug / coil wires were switched it would not run at all.
Well it was running with them backwards. I got to take it out this morning and it ran 100 times better. Fired up much better. Still isnt perfect but much better. One of the spark plug boots came apart when I was changing the spark plugs on Thursday so I just got a whole new coil for it rather than fixing the boot. It ran ~15 mph with me and my boy in it. Definitely need to get the throttle fixed now. Theres a ton of slop in it when going from start to fast etc....
 
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