What motor is this?

[nitrotweaker]

My freind has a johnson on his boat.The modle # is rdsl-26r and the ser# is j2458174
It says its a johnson super sea horse.
We are tring to get the motor to run a bit better than it does.It doesnt have any throttle range to it.It runs like a light switch.And when we try to troll with it it will idle for a while and then rev up with out hitting the throttle.The motor has great compression.I think it is in the timming or advance.First I need to find out the year and the horse power.The boat only goes about 18 mph as far as the gps says and for the size I would figger it would have a bit more.Thanks

 

[CATransplant]

Re: What motor is this?

That's a 1964, long-shaft 40hp Johnson you have there. Sounds like a carb problem, at least. You say it suddenly speeds up when you're trolling? what happens at wide open throttle.

If you can describe more of how the engine acts, we can probably help you pin down the problem. Right now, I don't quite understand what it's doing, overall.

As always, check the spark. If the carb hasn't been cleaned thoroughly and a new carb kit installed, that's probably on the work list. The speeding up while running at a low speed could be fuel starvation, leading to a lean condition, especially if it finally dies. That could be a fuel pump or other delivery problem.

When you say it only goes about 18 mph...we need to know what size boat it's on.

 

[rjezuit]

Re: What motor is this?

A bad coil dropping in and out could cause that. When it fires, it revs up, when it's not, low power. Check the coils with a spark tester, and also see if you can peek at them through the point setting hole in the flywheel. If they are cracked or look like they are covered in salt, they need replacing. Rick

 

[nitrotweaker]

Re: What motor is this?

It seem's to be running rich.The motor is in a 16ft deep v.I am going to go over there right now and pull the carb off and see if theres any goo in it. The reason is am suspecting the spark side is because of running at a steady idle and the rmp go up as much as 2500 rpm and you have to mess with the throttl to get it back down.Does this motor have a cdi box or does it have points?

 

[tashasdaddy]

Re: What motor is this?

http://forums.iboats.com/showthread.php?t=167352