Older 25hp Johnson

[tucker99]

Hi,
Looking at the boat below. Owner said the motor starts right up and runs great. Whenever I by an older motor I ususally change a bunch of stuff. I only have experience on larger Yamaha's and don't know anything abou these older Johnsons. I usually change, stats, water pump, fuel pump, fuel filter, and lower unit oil. What should I be looking for on this older engine. Thanks guys!!

 

[nccatfisher]

You can check the thermostat for function, other than that I would change water pump and lower unit oil, plugs and give the fuel lines a good look/going over and if all checked out enjoy it. Look at the paint on the head etc. for obvious signs of ever being run hot (hopefully before you purchased). Those were very solid old motors.

 

[Weldorthemagnificent]

Looks to be around a 95ish motor. Also looks like it's been taken care of. X2 on the things mentioned above. Extremely good motors. I run the 35hp version from 83 and it runs perfectly and looks nowhere near as nice. The perfect motor for a 14-16' fishing boat in my opinion.

Sent from my CLT-L04 using Tapatalk

 

[Pappy]

Have the owner put the boat in the water and demonstrate that the engine runs.
The engine you are looking at is an extremely good engine. If the engine will idle down to a nice slow idle in gear that is a clear indication that the engine is well sealed internally.
check the gear oil for water but that generation of gearcases was pretty bulletproof.
Fuel lines will be old, primer lines will be old.
I would purchase a complete water pump assembly and do it right. If you are not of that mentality then check the upper cup for wear marks that you can hang a fingernail in, same for the lower wear plate. if you have any that you can hang a fingernail in the by all means replace the complete pump.
The engine was designed to run on Champion spark plugs and they do a great job in the engine.

 

[tucker99]

Not at all familiar with that gear shift lever. Kinda sticks out, Is it plastic and prone to breaking? I've read posts about bad brushes on the starters. Is parts.net the best source for maintenance parts, etc? That is a short shaft engine, correct?

 

[jasper60103]

Not at all familiar with that gear shift lever. Kinda sticks out, Is it plastic and prone to breaking? I've read posts about bad brushes on the starters. Is parts.net the best source for maintenance parts, etc? That is a short shaft engine, correct?

I had the same motor in a 30hp. It served me well for a good while.
Parts are still easy to find. No worries there.
Looks to be a short shaft by looking at the transom step down, but you
can confirm with the part number tag on the side.
Take the boat/motor out for a shake down as Pappy suggested if possible. No sense going into with
problems if you can avoid it.

 

[RaisedByWolves]

Not at all familiar with that gear shift lever. Kinda sticks out, Is it plastic and prone to breaking? I've read posts about bad brushes on the starters. Is parts.net the best source for maintenance parts, etc? That is a short shaft engine, correct?

Best gear shift ever.

Try and break it.

 

[tucker99]

Ok, pulled the trigger on the boat, paid $1,000. Good ole boy lite it up right in the parking lot. Touched the button an it started. Would not sea trial or put it on a hose. In a storage lot take it or leave it. Engine is 1993 model J25RETS, S/N 0341272. Checking used factory manuals and seeing P/N 508283 & P/N 507265, can someone give me the correct part number? Lifting mechanism missing bolt to hold on stb bracket, can't find a release button (probably need an owners manual). Only port side holds up engine. Trim pin is missing and engine pushing against horizontal brace between clamp brackets. Throttle grip really tight and is missing rubber. Missing silencer and seeing some spliced wires, looks like original coils. Have to research freeing up throttle for sure. Will also start on full throttle, that shouldn't happen. Yea, the LU oil was milky and the prop shaft has about 1/8" free play in and out, bad? Thanks...

 

[jasper60103]

Ok, pulled the trigger on the boat, paid $1,000. Good ole boy lite it up right in the parking lot. Touched the button an it started. Would not sea trial or put it on a hose. In a storage lot take it or leave it. Engine is 1993 model J25RETS, S/N 0341272. Checking used factory manuals and seeing P/N 508283 & P/N 507265, can someone give me the correct part number? Lifting mechanism missing bolt to hold on stb bracket, can't find a release button (probably need an owners manual). Only port side holds up engine. Trim pin is missing and engine pushing against horizontal brace between clamp brackets. Throttle grip really tight and is missing rubber. Missing silencer and seeing some spliced wires, looks like original coils. Have to research freeing up throttle for sure. Will also start on full throttle, that shouldn't happen. Yea, the LU oil was milky and the prop shaft has about 1/8" free play in and out, bad? Thanks...

Found an OMC serivce manual on ebay...

1993 OMC JOHNSON EVINRUDE 9.9 10 15 20 25 28 30 35 HP SERVICE SHOP MANUAL 508282

https://www.ebay.com/itm/1993-OMC-JOHNSON-EVINRUDE-9-9-10-15-20-25-28-30-35-HP-SERVICE-SHOP-MANUAL-508282/324116694103?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D225086%26meid%3D5286b6ea274344599631b5309a8aa859%26pid%3D100005%26rk%3D1%26rkt%3D12%26mehot%3Dpf%26sd%3D324109581988%26itm%3D324116694103%26pmt%3D1%26noa%3D0%26pg%3D2047675%26algv%3DSimplAMLv5PairwiseWebWithSearchFilter&_trksid=p2047675.c100005.m1851

 

[tucker99]

Thanks, I just saw that. My model number is slightly different, J25RETS. Not sure what the S means, the manual covers just J25RET. Ideas? Thanks...

 

[jasper60103]

Thanks, I just saw that. My model number is slightly different, J25RETS. Not sure what the S means, the manual covers just J25RET. Ideas? Thanks...

I heard the last character represents changes during the model year. It doesn't affect the service manual.

 

[RaisedByWolves]

Ok, pulled the trigger on the boat, paid $1,000. Good ole boy lite it up right in the parking lot. Touched the button an it started. Would not sea trial or put it on a hose. In a storage lot take it or leave it. Engine is 1993 model J25RETS, S/N 0341272. Checking used factory manuals and seeing P/N 508283 & P/N 507265, can someone give me the correct part number? Lifting mechanism missing bolt to hold on stb bracket, can't find a release button (probably need an owners manual). Only port side holds up engine. Trim pin is missing and engine pushing against horizontal brace between clamp brackets. Throttle grip really tight and is missing rubber. Missing silencer and seeing some spliced wires, looks like original coils. Have to research freeing up throttle for sure. Will also start on full throttle, that shouldn't happen. Yea, the LU oil was milky and the prop shaft has about 1/8" free play in and out, bad? Thanks...

Correct PN for what?

The throttle being tight shouldnt be hard to fix. If you look on the end of the grip closest to the engine there should be a button (2?) that you depress and the handle will slide forward.

As far as the silencer, the one for the carb? They usually get tossed early in a motors life.