Advice on Evinrude 6HP motor

cruisercan

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Hello,
First time poster here.
I would like to buy a small outboard motor for my inflatable boat. I saw a 1979 6HP Evinrude for sale locally (model 6904E). See photo. The seller selling it is for parts because it has low compression. He's asking $200 CND.

My question is, without seeing the motor, what would be a common cause for low compression in these motors? I understand the possibilities are endless, such as a stuck valve, head gasket, pistons and rings...etc. but just wondering for those who are familiar with these motors if is there is a known common cause for low compression in general.
Also, I think the $200 he's asking is quite steep. knowing the risk, what would you say a fair offer can be?
Cheers
 

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racerone

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Rule out the stuck valve on this one !----------Head gasket is a common fault.-------I would not hesitate myself on that motor.----But I have all the parts to fix whatever would be wrong too.-------Where in Canada ?------If you have to pay a shop to replace pistons / rings it may not be a good deal.
 

jimmbo

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Without seeing the engine it is impossible to say what is the reason for the low compression, all the one you mentioned are the common causes, except the valve. The rest of the engine might be fine and could be a source of parts if you had another 6 hp. Offer him $75, you can resell it for that easily. If you are in the US that works out to $58 bucks?
 

cruisercan

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Thanks guys for the response. much appreciated

I am in Alberta. If I get it, I plan on doing the work myself. I am a home mechanic and have a well-stocked garage. But I don't have any parts (never owned an outboard motor before). Kind of hesitant on this one. A head gasket is simple enough (and cheap), but if it needs rings, pistons, etc. Cost can rack up pretty quick.
How much (approx.) would a head gasket cost for this motor? Also, any idea on the price of a set of pistons and rings?

The seller is obviously targeting repair shops who may be interested in the motor for its parts (hence the price), but for me, I plan on using it, not re-selling. I'll offer him $100 and if he doesn't take it, I will move on.
 

racerone

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Sierra gasket is about $20.--------Factory gasket is double that at least.----Judging by the cosmetics it is a low hr motor.--------I would not hesitate at the asking price.
 
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flyingscott

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See if a compression test has been done on the motor and get the #s if you can. That motor is not a high compression motor so some people make the mistake of thinking they have low compression.
 

cruisercan

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Thanks again for the replies.
Forgot to ask, is it an air or water cooled motor? Also, is there a manual I available for downloading online (owner's or service)?
Regards,
 

cruisercan

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Well, he declined my offer. I guess the search continues.
Will post again if I manage to get/locate another motor.

Thanks for your help and advice. Truly appreciated.
 

F_R

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If he isn't too far away from you, it probably would be wise to go check the compression yourself.
 

Crosbyman

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dont give up on it... looks half decent but that is only outside the motor not inside.

he is willing to have you do a compression test ( get/borrow yourself a meter) ????


squirt some WD 40 in the pistons to loosen things up ... pull the starter cord a few times and retest (spark plugs out)

if both cyl are almost the same and around 75psi go for it ! but it is up to you

in any event you will need to learn to maintain this oldy lots of info and advice available .
i have a few much older 5.5and 7.5 from the 50's that run like a charm this one should also run fine if it was fed some good oil in its life and did not go for a swim



btw out of all my oldies I have never cracked one open to mess with pistons, rings etc....
​3x3hp, 5.5, 7.5, 3.9 merc 4hp71, 2x 9,5 sportwins just sut lucky I guess..... my lastest 3hp was $20 .. ugly but 80+ on both cyl.

​p.s edit... at least do a test for strong sparks on both plugt ...that engine has ignition parts unknown to me and could get expensive. I am only familiar with the older ignitions on mid 50 early 60,s motors. ...as is said.. up to you
 
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racerone

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No that motor should have the ultra reliable electronic ignition.---------Just did one that had not turned for 20 years.---------Had beautiful spark without any money spent or adjusting anything.
 

ondarvr

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I have three of those motors and there's no way I would spend $200, even Canadian, on a low compression one without knowing what the exact issues is.

​I'd sell mine in great running condition for not much more than that.
 

oldboat1

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If new to outboards, an older non-CD version might be better imo -- '76(?) or earlier. All parts are easily available, and comparatively cheap. Check out garage sales -- sheds and basements get cleaned out in the Spring.... Maybe take some J/E model numbers with you to help identify motors. Take a compression tester with you.
 

cruisercan

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Thanks for the post and advice.
What's a "non-CD" version? Are you referring to models which start with "CD"?
Why CD models are not recommended for beginners?

Cheers
 

flyingscott

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Non CD version means it has a magneto ignition with points and condensers and coils are generally under the flywheel. The CD ignition is a Capacitor Discharge Ignition It uses a box mounted to the block to do the same thing as the points and condensers. The coils are also moved to the block by the sparkplugs. I would recommend a cd ignition to anyone it really is a great ignition. I don't believe points and condensers are cheaper or easier to get as both ignitions have great availability. As far as cheaper thats up in the air I have seen CD boxes last 20 yrs on some motors and and generally points and condensers last about 5 years.
 

oldboat1

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Don't disagree, but think CDI can be tougher to troubleshoot for a beginner (IMO), and parts can be expensive. If you like to tinker a little with fine tuning, you can probably do a little more of that with the magneto systems. But it depends on what you run into -- if a neighbor gives you a motor (CD or mag) don't turn it down.
 

Crosbyman

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Older points/condernser ignition are like the old TVs... with easy to swap electron tubes.

My TV repair capabilities died when electronics came in....


​purely has a hobby I gotten much personal satisfactions learning fixing 50$ motors with new coils points condensers. My 5.5 and 7.5 mid -late 50s and 9.5 mid 60s work like a charm all day and don't complain. So does my gas sipping 2005 75hp ETEC but I dread the day the EMM computer will croak
 

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