4.5 Johnson Outboard - Power Question

[starcrazy]

Motor ? 4.5 Johnson Outboard
Model ? J5RHCNR
Serial # C8142952

I believe it?s a 1985

Hi everyone, relatively new to the forum, but I have a question regarding my 4.5 Johnson. I just recently purchased it, it seemed to be a good deal and of course, myself not knowing much about them, I purchased it. Anyway, enough of my lack of knowledge. I was able to take it out and it starts with no problems.

Here is the problem, I was going along and I was pretty impressed with it. It was doing 7.5 mph, then within 10 mins. it slowed down to 4.5 mph. I thought the cable might be stuck or something, but that is not the case. Fresh fuel and new plug.

I was wondering if any of you had any ideas what could have caused it to run flawlessly for 10 min. then suddenly go to half the power.

Thanks in advance.

Wayne

 

[nwcove]

Re: 4.5 Johnson Outboard - Power Question

id put my money on a bad plug, even if they are new. i have the same motor, evinrude 4.5 1985. (if your motor still has the decal saying 100:1, disregard it. mix at 50:1)

 

[Rick.]

Re: 4.5 Johnson Outboard - Power Question

CN would make it an 82 by my calculation. Plugs are a good cheap place to start. Could also be a failing coil (when hot) so if plugs don't fix it try a spark gap test when it's giving you problems. These engines run very smooth on just one cylinder but the tell tale is a lack of power as you've described. Best of luck. Rick.

 

[starcrazy]

Re: 4.5 Johnson Outboard - Power Question

My bad, I guess it was just my idea of hoping to have a newer motor, lol

Thanks for the information, At least I know it can be repaired, and for a descent price.

Thanks

WR

 

[starcrazy]

Re: 4.5 Johnson Outboard - Power Question

Purchased new plugs this week. I won't have a chance to test it out until later in the week. thanks for the information.

Wayne

 

[jimbo_jwc]

Re: 4.5 Johnson Outboard - Power Question

My 87cc 4.5 hp Johnson Sea Horse Model J5RC5 acted like this when I first got it . After using a few times it ran a little better , Fresh gas I thought , started to notice fuel leak around bowl gasket . Ordered carb kit and it turned out to be a saturated cork float . Runs strong now . Sweet little motor as I was upgrading from a couple of 1949 5hp Johnson Sea Horses .