what are things the shop will tell me?

[rbig]

Got a '77 115hp Evinrude. Good engine. Having some problems.

My daughter says the RPMs drop off, at any throttle setting, smoothly.

To me, this is something that I will take to the shop.

What are several things I would likely hear? In a way, it sounds like coils to me. I would appreciate any thoughts on it.

 

[Daviet]

Re: what are things the shop will tell me?

Could be fuel problems, ign problems.
Before I took it in I would do some simple checks, spark and compression and see what you get.

 

[tx1961whaler]

Re: what are things the shop will tell me?

They'll say "We don't work on motors that old"
It's hard to tell what the problem can be from the description, but it seems unlikely that all 4 coils would act up at the same time, and it sure wouldn't be smooth.
Is this just a couple of hundred RPMs, or does the motor die?

 

[HighTrim]

Re: what are things the shop will tell me?

Maybe dropping a cylinder.

Do you have an inductive timing light? If you run the boat with the light hooked up to a plug wire, waiting for the RPM drop, you can see if that particular cylinder is dropping.

 

[rbig]

Re: what are things the shop will tell me?

The run down is smooth. The reson I said coils is because loosing some coils give you smooth operation, just nowhere near the power you once had.