Need help

[hamms-scooter]

Can someone tell me how to read a model number and serial number to tell what year my boat motor is? I bought a 25hp johnson longshaft the guy said was a

'72. It needs a little tlc with a gear on the tiller arm going into the back gear that runs the throttle.

[jwmiller33]

Johnson motors are pretty simple. Usually the model numbers are found on the nameplate that is located on the mounting bracket. I have a 79 Johnson and it has the serial number and model number on the nameplate that is on the mounting bracket. Then you can look up what year it is and all the specs it has (HP, elec/pull start, shaft length, etc) by the numbering in the model number. If you post on here what your model # is, I can look it up for you and give you all the specs. Or, just do a simple google search for johnson model numbers and you should figure it out pretty easy. The serial number is more for individual motor identification (I think)... The model number is what your going to want to tell you the year/HP/specs/etc

I believe the "tlc" you are describing is the linkage, fyi.

[hamms-scooter]

Thanks Jake. The linkage is messed up. The gear that is attached to the throttle arm is cracked so I would like to get that fixed as id left me stranded on sunday. The motor would run but without turning that it would just idle and nothing more. trolling motor got me back. I knew headed out it was a trial run so now it will be getting fixed. Anyway the model number is 25R70E which makes me think it's a '70. R must be for recoil. Your thoughts?

[boatfixer]

You are correct

[hamms-scooter]

Thanks for the help guys.

[jwmiller33]

glad to hear of the new purchase for your boat hamm scoot! have you had the motor in the water at all before you bought it? if so, how does it run? if i remember right, you have a 16ft boat, right? that should push that thing pretty good

[hamms-scooter]

I have a 1970 16' starcraft and now a 1970 25hp johnson. I wanted a newer motor then this but I picked this one up for $250. I figure if I have another $150 into it I will be happy with that. I was unable to run motor before I bought it and took the guys word for it that it ran well. I got it home and tinkered with the linkage a bit and had it fixed. Took it out and the fitting from the hose to the motor was leaking as I primed the ball. the fitting on the hose is new one on motor looks old. Never had an issue with this before. The motor started up and was really pretty quiet. Idled very well....till the pressure was gone from the fuel connection. Got it going again and we were off. I had us going down the river at 20.4 mph with my dad in it also,went to open it up some more and the vertical gear in the linkage that connects the tiller arm to the motor (the one I had fixed as the guy had it on running out of teeth when you turn it) skipped a tooth on other gear and then came loose. I took it off out there and tried to set back into place and it broke. Ended up running MinnKota rest of the day and was bummed out about the 25. Since I was unable to test run it at guys house he said to bring it back and I could get my money back....That was a joke as he will not return any of my phone calls. I am thinking with a little tlc at the local marine shop it will be a good motor for me even though its older then I would like. After all its a JOHNSON! Things I would like fixed: That linkage, gas fitting on engine, have throttle parts under hood checked and make sure there isn't something hanging up or causing the twist grip to go so hard. I looked into a new cowling at TCO and it was only 50 bucks if I want it to look a little better. I mostly care about function over looks but if things work out I can see fixing it up. Once agin can't believe how quiet it was for a 2 stroke. Should as a little more speed then my 15hp as I was getting 17.9 with just me in the boat. Hope it doesn't cost to much for part for this year of motor.

[hamms-scooter]

PS my dad said any running boat motor of that size is definatly worth what I paid. Happy to hear that

[hamms-scooter]

What plugs are recommended for this motor? It has a pair of champions in it now.Would NGKs be better?

[jwmiller33]

are you sure you have a johnson fitting on the end of your gasline? what kind of motor did you have before you bought this new one?

[hydro]

At $250.00 you got a good deal, even needing some work.

Here is my two cents for you; first, the Champion plugs are fine, keep them in there but check to see if they are carbon fouled then set the gap to .035".

Next, as mentioned above, make sure the gas line fitting is a correct OMC part, then go to your dealer and get an o-ring to replace the one in the fitting. You can poke the check ball back with a dull nail and the o-ring will come out. They get torn with use and cause the leakage and running problems you describe. Make sure the male fitting on the motor has no sharp burrs that can damage the new o-ring.

You linkage is a bigger job, but if the gear teeth are breaking because things are hard to turn, you need to do this R&R over the winter. Get the proper tools, including a puller and remove the flywheel. Once the nut is off, put the puller on, tighten a little bit, then rap the puller with a big hammer. Not too hard though, you just want to pop it enough to release the flywheel from the shaft taper. Underneath is the ignition plate which the linkage turns to advance the spark and also to move the carb throttle plate. It's held on by a couple of thin head hex bolts and sliding plates on the underside. I bet the 40 year old grease under there is quite stiff, so clean it off, re-lube with white grease and put things back the way they were. Then fix your linkage gearing. Things should move much easier when you are done.

Last, drain the gearcase and refill with OMC gear lube. The old oil should come out blackish brown with no water. If you see water or the oil is milky looking you will need to get the gearcase serviced to find and fix the leak. New gears will cost more than you paid for the motor so this is maintenance insurance well worth doing.

[hamms-scooter]

First off thanks for the help guys. The fittings are all johnson /evinrude, I noticed a little paint that flaked off on the fitting in the motor. Hydro, You are dead on with the grease causing the friction. I brought the motor into a good marine shop and he said that I did good to get for 250. He saw it had a new head gasket and I told him I replaced the oil in lower unit and it was dark with no water. I explained the problem with the gear and he said no problem he would pull flywheel and regrease as you mentioned. I know none of this is hard but I am not a mechanic and like to know things are done right. When i am out I like to fish not work on things... Peace of mind you know. Thanks for all the help and i will let you know how it turns out. One more thing was to have him run the engine and make sure the clutch dogs are good.