Topic: 1973 Evinrude Mate 2HP Issues – Antique Outboard Motor Club,Inc

This topic has 49 replies, 12 voices, and was last updated 6 years, 12 months ago by fleetwin.

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April 2, 2018 at 1:17 am #9536
shane-r13
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I’ve got 1973 Mate 2Hp thats giving me heaps of trouble. First it didn’t have spark, bought new coil and condenser. Points looked good, cleaned and set at .20. Got spark now. Removed carb cleaned and rebuilt. Has fuel in bottom end now. Changed piston rings, only has about 50psi now. Obviously has low compression but i figured when misting fuel into spark plug hole and turning over id get some fire. To me it almost seems like the timing is off, but that cant really be possible can it? Cant for the life of me figure out why she no go. Any pointers? Thanks!
April 2, 2018 at 1:28 am #73337
david-bartlett
Participant
Shane,

I had one of those motors for a long time. Good runner if the points and fuel were clean. I am going to bet that your issue is compression. Just too low.
April 2, 2018 at 1:31 am #73338
garry-in-michigan
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Lifetime Member
Worn out from using 100 to 1 oil mix ? ? ? 🙁
April 2, 2018 at 1:34 am #73339
david-bartlett
Participant
Could very well be!

quote Garry in Tampa:

Worn out from using 100 to 1 oil mix ? ? ? 🙁
April 2, 2018 at 1:52 am #73341
shane-r13
Participant
quote Garry in Tampa:

Worn out from using 100 to 1 oil mix ? ? ? 🙁

Unknown the mix that was used previously. Picked it up in this condition, just trying to revive it.
April 2, 2018 at 1:55 am #73342
shane-r13
Participant
quote david bartlett:

Shane,

I had one of those motors for a long time. Good runner if the points and fuel were clean. I am going to bet that your issue is compression. Just too low.

Any ideas on where to start to see why I have such low compression? As stated earlier I replaced rings (mainly because I broke them during removal, compression before hand was unknown.) Cylinder walls and piston "look good". No scoring or anything that stands out. Crank seal? I replaced head gasket and exhaust gasket while I did the rings btw. Hate to toss this old girl out, would love to get her running for a great trolling motor.
April 2, 2018 at 10:00 am #73344
billw
Participant
US Member
A good one will have 100 psi, so you have a long way to go. Did you check ring end gap before reassembling? Not sure what the spec is but it’s probably in the .010 to .015 range. They absolutely get worn out and also are prone to rust pits in the cylinders, from being carried around and stored upside down or what ever. (They are often found seized up.) They also like a good head gasket, although hopefully that’s obvious. Sometimes you can get them to fire briefly by putting gear oil in the cylinder and immediately trying to start it. It my fire or run for a few seconds and quit; but it helps verify you have a compression problem.

Long live American manufacturing!
April 2, 2018 at 12:36 pm #73348
fleetwin
Participant
US Member
Well, the compression surely sounds low, especially if you just replaced the rings. Did you orient the piston correctly? The sharp side of the piston deflector should face the right side/intake side of the powerhead. Nonetheless, improper piston orientation would not really affect compression. Like others have said, add some two stroke mix directly into the plug hole to see if the engine will fire, perhaps the compression will come up…
It is possible that your compression gage reading is inaccurate, try a different gage…
April 2, 2018 at 3:49 pm #73356
joesnuffy
Participant
I just wonder did you break another ring or 2 putting it back together? And as the others said piston ring gap of the rings you installed is what, and make sure if you removed piston it is oriented correctly. How exactly did you break the rings to begin with when tearing it down are you sure you broke them or might they already have been broken from a bur or something in cylinder. Just my thoughts on this.

Joe

ps if adding some 2 stroke oil into the cylinder raises compression then its most likely a broken ring or to much ring gap in my humble opinion since you said cylinder and piston looked good. You should be able to feel what the compression feels like just turning flywheel by hand before and after oil is added even before you try your psi meter or try and start it. Also did you clean the ring groove very well on the piston before putting new rings on it making sure the new rings didn’t bind in piston. I normally use one of the old broken ring to help clean the grove.
April 2, 2018 at 4:57 pm #73358
shane-r13
Participant
Ok, so this was seized when i received it. PB blaster etc and freed it up. Removed piston to clean rings and and ring grooves. Thats when they broke. I didn’t measure ring gap. I just ordered them and tossed them on, I assumed they would be to spec. I took the head off and looked inside again, it is pitted and has surface rust on one side of piston. How can I remove this? I havent removed piston again to check end gap or if I broke a ring installing. When I put oil into cylinder and turn flywheel by hand I can feel greater pressure, also now that the rings and cylinder has oil when I removed head and wiped cylinder clean and turned flywheel I can see that the pitted area does not get a layer of oil. I tired to take photos and will attach. It was kind of hard to get a decent photo. Thanks for the input so far guys.

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