25 johnson want start.

[duckhunter55]

heres my problem guys. i have a 78 25hp johnson manual start motor. My problem is a after taking lower unit and drive shaft off to check gears and then repalcaing everyting, which i pretty sure i did correctly, i go to take the boat out. After leaving dock going slow the motor starts to slow and finally dies. I go to restart but find rope hard to pull, but still pullable. I take boat home and remove lower unit, but the rope is still hard to pull and motor still want start back. Motor has good spaek and good compr. THe flywheel seems to not want to i guess turn over at end of pull. instead it keeps same strong tension the whole pull. I cant figure out whats wrong. any help greatly appreciated. thanks luke

 

[jbjennings]

Re: 25 johnson want start.

I'm curious, did you pull the flywheel and mess with or replace the coils? If so, you may have the coils extending out too far and binding on the flywheel. If you have lower unit off, there's no way you should have any problem pulling that motor. How does the pull cord pull with the recoil assembly off the motor? How does the flywheel turn by hand with the recoil assembly off? If your motor is only hard to turn when the lower unit is on, something must be binding in the lower unit. When you rebuilt your lower unit, did you make sure the bearings on the gears were positioned over the little stud things that slide into the holes in the bearing carriers? Sometimes, people forget to turn the bearing carrier until it slips over the stud things. You would have had trouble screwing your bottom cover on, if that was the case. I'm just trying to guess at your problem and I'm no expert. I just have fun tinkering with my old outboards. Your lower unit might not even be built like I'm thinking. You should be trying to localize what's binding, though.(As I'm sure you're doing) Is it the recoil starter, the flywheel, the drive shaft, or lower unit.
Hope this was helpful,
JBJ

 

[tashasdaddy]

Re: 25 johnson want start.

remove spark plugs and turn by hand are there hard places when you turn. remove recoil, clean and lub lightly. i take it that it is still hard to turn with the lower off, so that runs out the lower unit.

 

[rick_l]

Re: 25 johnson want start.

Question, when you put the lower unit back on, di you notice if water was coming out of the telltale when the motor was running. I had a motor which ran find for awhile and then would lock up. If water is not circulating it can cause the motor to lock up. When you put the lower unit on if you did not line up the water intake line with the gromlet you may not be getting any water to the block which can cuase the motor to seize up.

 

[duckhunter55]

Re: 25 johnson want start.

Ok, took plugs out and turned by hand. There is one spot during the turn where it does get tight then releases, but i think thats normal. Took recoil assembly off and it pulls fine, no binding there. Someone told me this could be an ignition problem, and he said that if th ignition was fried then it would make it harder to pull cause the ignition assists with the pull. Is this true? If it is ignition then how would i diagnose it and pinpoint problem? thanks for help!

 

[jbjennings]

Re: 25 johnson want start.

If it's binding anywhere with the plugs out, that sounds strange to me. It should be easy as heck to pull with the plugs out. Is there any rubbing or grinding noise when you turn the flywheel with the plugs out? If so, pull the flywheel and see what's binding. Once again, maybe your magnet could be rubbing on one of your coils.
JBJ

 

[Solittle]

Re: 25 johnson want start.

How were you able to take a compression reading if the engine was binding and what were the compression readings?

 

[duckhunter55]

Re: 25 johnson want start.

I havent checked compression yet. Someone gave me a compression checker but i think it might be for a car or something because i cant get the rubber end to go into the plug hole, if thats how it goes. I tried just holding tight against the hole but nothing happens when you pull the rope. Also should all plugs be out when checking or just the one your checking? I seen another guys post above who has a problem just like mine but his will start.