Help with 1974 Evinrude Johnson 25 outboard boat motor?

[bobhill8]

Hey there, My 17 year old son recently bought an old boat with an old motor. He is very mechanically inclined and has worked on chainsaws, lawnmowers, etc but we are unfamiliar with boat motors in general. I'm wondering if anyone has any resources or knows of a Sambaesque site where he could get some help. Youtube has been somewhat helpful but he is a little overwhelmed right now, not knowing quite where to start. We looked into finding an old "bentley" for the motor but even that seems a bit confusing. Any thoughts greatly appreciated. Bob

1974 Evinrude Johnson 25 outboard
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1986 Westy
1971 Squareback

[mark tucker]

it's just a engine. bolted to a diff with a drive shaft inbetween. I threw away my old 69 40 hp evenrude 2 years ago. had lost of good time with it,a fre rebuilt foots,a few water pump impellers, points,crabs rebuilt, put a bigger carb on for more power but never ran it again, oit sat for 2o more years got full of h20 when home in shed roofvfilled it....well it may of been ok but I didnt need it. I sold the speed boat it was on, it was serface drive on that boat.

[mark tucker]

if you do the points&condensor. I would try to source a old mallory brass condensor, many new china ones are shit....or go electronic. also probably be a good idea to put a impeller in the foot.be sure to use some water soliuable greessee in it.and never run it with no h2o it will rip the vanes off or wear them very fast or melt or all of the above, requireing a total water pump replacement.

[mark tucker]

and if in salt water always flush it reall good. realll good

[mark tucker]

run some ring free in it.( yamaha ring free) when fuel dries in the carb the jets got smaller...and the motor leens out and...burns a hole in the piston. always winterize properly and in spring run ring free through the first tank about half throttell max for the first tank of fuel.to clean the jets& rings. use synthetic outbaord oil for the mix.name brand only.Ive seen the off brands kill too many engines., yamaha or evenrude/jhonson should do fine. Yes I used to work on all that shit.certified yamaha&merc tech..long ago

[bobhill8]

Thanks Mark - should we try the ring free for the first start? We don't know when the last time it ran was. We don't even know what the oil/gas mix should be. Appreciate the help.
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1986 Westy
1971 Squareback

[Abscate]

Get all the old gas out of it, new spark plug, oil the cylinders with 10-30, pull crank until the oil is spit out.

Fresh gas, 25:1 to start.

Vrooom
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.ssS!

[skills@eurocarsplus]

you'll be splitting the drive to replace the water pump for sure. also the thermostat should be looked at.

if the tell-tale isn't pissing water DO NOT run it, you'll cook it in short order.

you'll have to separate the lower drive housing to access the shift lever bolt.

carb parts are pretty spendy and if yours has the composite cover with the mixture needle in it look for cracks. ANY air leak it make these impossible to tune in.

make sure your advance/retard plate moves freely as well

this is a 15 i did. yours will be pretty much the same


Link

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[bobhill8]

Thanks to my Vanagon cronies, Abscate and Skills. Much appreciated. The Boy is cleaning it right now - I will send him the video.
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1986 Westy
1971 Squareback

[mark tucker]

dont oil cylinders with 10-50!!!!! use fogging oil!!!! ENGINE OIL WILL GUM IT UP AND CRE8 ISSUES!!!! and cause ring sticking!!! never add engine oil to the cylinders or chambers or intake ports of any engine!! foging oil is what you use.or some synthetic 2 stroke oil, but sparingly. fogging oil is a spray foam oil that will not eff it up.

[mark tucker]

also when ever winterizing use the foging oil as per directions.it's good stuff.

[bobhill8]

Hey again, So we did a compression test on the two cylinders and got about 55-60 on each. No idea what they should be at. Thoughts?
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1986 Westy
1971 Squareback

[mark tucker]

rings may be stuck.if it will run run it.do so eazely with the ring free in it.no full throtell.a run tank or hose is fine. heat cycle it atleast 10 times. to see if they will release. if somebody ran it hard with dirty carb it may of burnt the pistons...witch is new pistons & rings rebuild time. sometimes you can replace the pistons other times they will need boring.dont know till it's inspected. aluminum from piston stuck to cylinder is common and can usualy be removed, if the cylinder is ok then just a new piston& rings. do not use any wd40 on any internal engine part as it will cause them to burn up.( wd40 will shed the oil from the part...thus no oil to cool or lube that part.) spraying in the cylinder should be ok.

[skills@eurocarsplus]

healthy engine should be about 115 or so cold.

how long has it been sitting? it's possible the rings could be gummed up

i'd see if i could make it run and recheck from there
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[bobhill8]

I got the Ring Free so we will get some of that in there with some fuel and see if we can get it to go. We have not tried to start it yet. Will update. Thanks
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1986 Westy
1971 Squareback

[JudoJeff]

Go on YouTube and search for your engine. Videos will show you how to do everything.
Parts are still readily available MarineEngine.com
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1989 Vanagon GL Westfalia Camper, Burned up on 7/31/16.
1987 Vanagon GL Westfalia Camper, Bostig & Rebuilt, sold
1986 Vanagon GL Westfalia Camper, Bostig Sold May 10, 2021
1999 Ford GTRV Westfalia camper (30% bigger Westy layout)

[mark tucker]

west marine has/can get most of the usual parts( h2o pumps,impellers,tunup stuff,carb kits etc) they are extreamly simple.even more than a vw.