Compression on 93 Evinrude?

[FNQCairns]

lol, i guess it was in his interest to suggest that it was broken if he wanted more money.........

I would be very interested to find the OEM specs for the engine as the guy i bought it from suggested it only had around 100 - 150hrs, the mechanic i took it to suggested it looked as if it was closer to the 100hr mark given the even compression, next to no smoke and something about a snake bore inspection???

There is none for compression readings that I have seen, it's done through general knowledge based on history. Anyway OMC never did have this as a solid spec i am sure, even on new engines it can vary but still be fully serviceable, imagine the new owner concerns if a manufacturer did list it's expected compression reading.

I just then googled and found everything from 110 to 130psi, this fits the general historic model of outboard engines, yours where all even and high which meets the most important pass criteria for this type of test...assuming all pots degrade due to normal wear and tear only, it still has 3000+hours of good serviceable life ahead.....it will not get there because the owner will kill a 2 stroke far earlier 99% of the time....I would be thrilled to buy an engine of that age with that reading and if it looks near brand new too! tickled is the word.

[Steeler]

3000 + hrs,only from those beautiful black ones.


Sorry could not help myself,been very quite lately no Fisher threads,no Toyo v Nissan v Disco.No 2 stroke v 4 stroke.

At this rate Mod5 will be able to take a WELL DESERVED holiday.

Steeler

[FNQCairns]

3000 + hrs,only from those beautiful black ones.


Sorry could not help myself,been very quite lately no Fisher threads,no Toyo v Nissan v Disco.No 2 stroke v 4 stroke.

Steeler

Given the circumstance you noted...no need to apologise

[NTMID8]

All good then my end mate and as you see from my "PS" in the above post all gauges will read different and as for the orginal poster if that engine, being a 1993 model, has the original cylinder head gasket i would suggest, as preventative maintainance, to replace the gasket and when doing it you can see the condition of the bores and also any signs of corrosion. To do this would be under $200 and worth it.

Cheers,

Huey.

So your suggesting replacing the gasket just incase? This wouldnt be seen as possibly creating a problem?

Engine looks to be in very good order, like i said though i have no issues with it just thought id see. I used to be a motor mechanic and car manufacturers would list a "norm compression ratio" but could not find the specs on outboards but now i know they dont list them

[Hornet Rider]

So your suggesting replacing the gasket just incase? This wouldnt be seen as possibly creating a problem?

Engine looks to be in very good order, like i said though i have no issues with it just thought id see. I used to be a motor mechanic and car manufacturers would list a "norm compression ratio" but could not find the specs on outboards but now i know they dont list them

The expense of replacing the gasket might be a useful investment for peace of mind. I picked up a 98 Johno 70 2st with 370 hours on it about 18 mth ago from an old bloke near coffs who had it from original, with service dockets. Beautifully kept outboard although he didn't ever cover it in the back yard & there was UV damage to the paint & decals. My mech did the service & suggested if I intended to keep it why not replace the head gasket, new head bolts & give the power head a slight shave if needed. Did all that & had a good look inside at the same time - no probs. I try to get out to deep tempest, hutchies, wide caloundra & don't mind pushing the weather a bit. On balance, I shouldn't suffer a head gasket blow out coming home, latter than I should be, in uncomfortable weather in the dark. Replacing your 93 gasket is good advice, but you'd have to decide on when, where & how hard you're going to work your motor.

cheers, HR