1991 Johnson 25 HP issue

[Borgey401]

Well today, I brought my recently purchased 25 hp Johnson out to the bay. I got out of the marina and gave it some throttle and all was fine. I was moving surprisingly well and was very satisfied. Well I realized I left a fishing pole in one of the holders and wanted to stop to take it out so it does not fall overboard. I took the pole out and put her in gear again and gave it some gas. This time tho my motor didn't seem like it wanted to go this time. I was moving without a doubt but at half the speed as before. I just wanted to know what could of happened? I am obviously new to outboards. I am thinking new spark plugs since I did not change them but what else can I do to help fix this issue?

 

[Daviet]

Re: 1991 Johnson 25 HP issue

If it is only runnig half speed and you have one carb and two cylinders, I would check the ign system. You can use a timing light to check spark and see if both cylinders are firing. Maybe a coil is bad, maybe a spark plug.
While you are checking things out, check the compression and get a base line of the condition of your engine.

 

[Borgey401]

Re: 1991 Johnson 25 HP issue

I checked compression when I purchased it and it was fine. I forget the exact readings but I know compression did check out good for sure. I am going to pick up a new pair of plugs tomorrow. Any particular brand you guys suggest? By the way I don't know if this helps but the model # is J25ELEID

 

[Borgey401]

Re: 1991 Johnson 25 HP issue

I went to West Marine today and purchased some Champion QL82C plugs. I had NGKs in but I decided to go with the more expensive plugs. Just wanted to make sure there's are correct. On the chart it says they're correct but want to just double check

 

[Daviet]

Re: 1991 Johnson 25 HP issue

In the parts book I looked in it calls for QL77JC4, but maybe that has changed, I am sure others will chime in and help out.

 

[jasper60103]

Re: 1991 Johnson 25 HP issue

I went to West Marine today and purchased some Champion QL82C plugs. I had NGKs in but I decided to go with the more expensive plugs. Just wanted to make sure there's are correct. On the chart it says they're correct but want to just double check

Yep, per the champion chart either will work for your motor, and I haven't noticed a difference using either plug. Did you do a spark test?

 

[larryg]

Re: 1991 Johnson 25 HP issue

you need to rip carb apart and clean it thoroughly,if it hasnt been rebuilt this is the time to do it. buy this kit REPAIR KIT-CARB 879054A 1 its worth the extra money unless you wanna keep rebuilding it.other kits break down to quickly cause of the fuel.make sure high speed jet is clean.get a bread tie and run it thru the jet spray with cleaner. book says for lower speeds use the 77, higher speed use the 82 plugs.get a open air gap spark tester and check the spark on coils.let us know results

 

[Hammer66]

Re: 1991 Johnson 25 HP issue

Did the motor seem to be running right? If it seems to be running fine is your prop slipping?

 

[Borgey401]

Re: 1991 Johnson 25 HP issue

Thanks for the replies everyone. I will test the spark and post results this weekend. I am starting to think that the high speed jet is probably clogged. I def. need new fuel lines on the motor also. I got a new alcohol resistant line for the gas tank but have not got any for the motor. I am thinking since the motor did sit for a year that it's a good idea to go through the carb and fuel lines. I am new to all this so I am not sure how to go about rebuilding a carb. I will purchase the repair kit right now and hopefully find someone that'll help me out with this project. I'm sure it can't be too complicated but I'm sure there's still things that can go wrong lol. I have not had a chance to run the motor in the bay since the new plugs yet either. I ran in a bucket and it seemed to run more smooth if that's possible. Well I will get back to everyone with results this weekend and once again thank you for the replies!!!!!!

 

[Borgey401]

Re: 1991 Johnson 25 HP issue

Well everybody I took my boat out on the Bay over the weekend and everything seemed to be great. The motor ran smooth n I seemed to get some good speed. I think she just needed to be ran a little since it was sitting for a year or so. I put some SeaFoam in the gas tank and ran that through the motor which seemed to help also. But all in all I am very satisfied with my boats performance now.