Late 70s/Early 80s Evinrude 115 help with compression check

jdkl81

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May 5, 2012
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Hi, I am new here and in researching older OMC stuff, I've seen there's a lot of expert knowledge on these forums so I thought I'd pass something by you all. I'm looking at a V4 Evinrude Starflite from this era. I am not sure of the exact model number because it appears someone has painted over the area where this information would be. The main problem I am having in determining if this engine is worth my money is that it is connected to a control box that is a total rats nest of wires and is missing the key, so therefore a compression and spark test isn't going to be easy. The first time I looked at it, we tried jumping the starter solenoid with no success, so I'm not sure if the owner was trying to jump the wrong terminals or if something more serious is wrong with the electric system or if I should begin to suspect the starter. What would be the correct terminals to jump assuming I disconnected this engine from the control box and just wanted to do a compression and spark check? Another option is that I could grab another red plug OMC control box off of the project boat that the engine would go on and hook up only the main engine harness. My control box differs from the one that goes with this engine in that the bad engine that is on my project had power tilt and trim where this engine does not. I live a couple of towns over from where this engine is located so if I go over and look at it again I really need to make a decision as to whether or not I should make this guy an offer or not. His story seems to check out and the price is reasonable but as of now it's a pig in a poke and I'd rather not have yet another project engine on my hands. I apologize if my information isn't good enough. I'm by no means an outboard expert but I'm reasonably mechanically inclined and willing to learn. Any help is much appreciated. Thanks again
 

Daviet

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Re: Late 70s/Early 80s Evinrude 115 help with compression check

You should be able to hook up the battery cables and use a jumper wire to jump from the battery side of the solenoid to one of the small terminals on the solenoid. If that don't work check to see if you get battery voltage to the starter when you jump the solenoid, if you are the starter could be defective. With the large red plug unhooked, I think you should have spark when the engine is spinning over.
 

Part-time

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Re: Late 70s/Early 80s Evinrude 115 help with compression check

your set of controls from your project boat will work on it. the power tilt/trim is a seperate set of wires from the control box that don't need to be pluged in for the controls to work.
to just check compression use a set of booster cables, ground to the engine block and positive directly to the starter where the wire from the solenoid is. Watch you don't toutch the starters body with the positive...
If the red plug is disconected and your batery cables are conected you can power the starter directly with the booster cable and you will have spark if all is good.
I think 120psi is a good compression for those motors, all the good running ones that I've tested anyways.
 

jdkl81

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Re: Late 70s/Early 80s Evinrude 115 help with compression check

Hey thanks for the quick responses! I let him mess with it last time since it wasn't mine, but I don't think he ever tried putting voltage directly to the positive on the starter and grounding the negative. I'm a little suspicious of the starter itself to be honest. I know that these motors could be pull started but I guess that wouldn't actually spin it over fast enough to give me a good idea of what the compression really is or would it? I'd imagine a healthy V4 would put up a fight even with all the other spark plugs out. One last thing...does anyone know if the starter from my 84/85 Johnson V6 would work on this engine or were they different? Thanks for answering the stupid newbie questions!
 

Part-time

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Re: Late 70s/Early 80s Evinrude 115 help with compression check

I don't know if the starters can interchange or not but they're not the same part numbers so I would guess no!
 

jdkl81

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Re: Late 70s/Early 80s Evinrude 115 help with compression check

Anyone have any thoughts on whether manually pull cranking this engine will give me a good idea about the compression or if I really need that starter to work to get a good idea of whether it's good or not? Thanks!
 

Part-time

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Re: Late 70s/Early 80s Evinrude 115 help with compression check

if you pull all the plugs out I can't see why not.
 

jdkl81

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Re: Late 70s/Early 80s Evinrude 115 help with compression check

Yeah I was thinking about that earlier, seems like I'd only be pulling against the cylinder I'm testing, it shouldn't be too bad. I'll let you guys know if I go test it and what I decide.
 
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