1978 Evinrude, 35 HP starter will not spin the fly wheel

Webekin

Petty Officer 3rd Class
Joined
Nov 7, 2022
Messages
88
So my grandson and I are working on a 35hp Evinrude made in 1978. It will not spin up, I removed and cleaned and polished the starter components, to encourage it to work properly. Still not spinning up. Removed a starter from my 1982 Johnson 35HP and same issue will not spin, engages but fails to spin.
Soooo, we determined that we had back pressure??? Removed the prop to access the exhaust port, found more dirt/debris than we can remove with out dropping the lower unit, to prevent pushing it back into the drive shaft/exhaust area.
Is this a reasonable solution to the problem of not turning over faster? If I remove the plugs, it will spin over very fast. replace one plug, back to no spinning.
Thanks in advance,
Webekin
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
37,813
Starter should at least turn the flywheel 1 or 2 turns.-----If starters are indeed good then remove powerhead to clean out exhaust housing.
 

Webekin

Petty Officer 3rd Class
Joined
Nov 7, 2022
Messages
88
Yes, it will spin the '82 with both plugs in. We will be cleaning the exhaust today. Webekin
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,224
I find it hard to believe that exhaust could be plugged enough to prevent cranking. I think there are other issues involved here. Be sure to let us know what you find.
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
37,813
But the poster is pretty sure the plugged exhaust is the issue.-----I wait for the outcome on this one.
 

rolmops

Vice Admiral
Joined
Feb 24, 2002
Messages
5,419
It never hurts to clean stuff up, This could be a case of plugs that screw in way too deep or simply a battery that is too weak to deal with the compression that this engine produces. A good fact that was mentioned is that without the plugs , it turns over just fine. That to me is a sign that a plugged lower end is not the problem.
 

oldboat1

Fleet Admiral
Joined
Apr 3, 2002
Messages
9,612
Battery needs to be charge and load tested (auto parts store). All wire ends in starting circuit need to be bright and shiny (sandpaper). If still no success, remove starter and clean it, perhaps replacing brushes (carb spray works for cleaning, but be absolutely sure the starter is completely dry before trying to start).

Alternatively, jump the boat battery from your car or truck (pos to post on side of boat starter, neg to starter bracket). If boat cranks, suspect a battery problem (have it tested and perhaps replace).
 
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