Still Need your Help Please

[warstoryz]

Hi. Still need some help with my Johnson 115 4 cyl. made in 1973
One of the members here gave me some valuable information regarding the problem I am having with intermitten power loss. My motor will run fine in the test tank or when it is just idling, but on the water it can be running along at 100% face and smooth, then all at once the power drops to about 25%. This problem seems to be more of a first hour on the water thing, and usually happens about 1/3 as often later in the outing. The fellow who gave me the advise said the coils could be arching, but in the test tank, when I ran it at night toi look for an arc, I could not find any. Doing that under high speed load conditions on the water is pretty much impossible, so i am wondering if there is a way to test the coils to at least fingure out where the problem might be coming from? If not that, any other ideas would be mush appreciated. Thanks, J

 

[licketdsplit756]

Re: Still Need your Help Please

this is just a thought. maybe others can relate better with this. a module on a car will act the same way when it gets warm will cut out. dont know that much myself. but would be interesting to also know if something like that could cause that problem such as the rectifier getting warm ??sorry im of no help. maybe this will lead another in the right direction. good luck

 

[Molaker]

Re: Still Need your Help Please

No help on the module, but unless you've determined you are losing 1 or 2 cylinders when the power drops back, I'd be more inclined to believe your problem is fuel related. Does the fuel bulb stay firm? Is you gas tank venting well? Do you have a pinched fuel line (inside or out of the engine cowling)?

 

[Silvertip]

Re: Still Need your Help Please

A fuel primer bulb does not stay firm once an engine is running. As soon as the engine starts fuel is being "sucked" through it, not forced through it. The bulb should not be sucked flat though. However, as soon as the problem occurs, have someone squeeze the primer bulb a couple times to see if the engine picks up again. If it does you have a fuel delivery problem. If not, it's very likely an ingnition problem. At the time of failure, if you are running with the engine cover off, pull spark plug wires one at a time, refire the engine and see if runs differently. You should be able to isolate the problem that way. That process obviously won't work if after the failure and shutting down, the engine restarts normally.

 

[Fisherman '78]

Re: Still Need your Help Please

I am having similar problems with my '67 Johnson 100 hp engine so I know the frustration. I think I have my problem figured out, so I'll walk you through some tests I applied. You could be running on three cylinders. This problem might go unnoticed in the tank, but become apparant under a load. First, run your engine in the tank and carefully pull one spark plug wire off at a time. After pulling the wire off the plug your engine should noticeably lose power. If this happens return the wire and check the next cylinder. If all your cylinders are running properly, then examine the fuel line as silvertip explained. If a cylinder is not running, check the plug and wiring, and then make sure the cylinder is getting fuel. If only one cylinder is not getting fuel you'll have to backtrack from it and figure out why. Good Luck!

 

[ezeke]

Re: Still Need your Help Please

I read your earlier post and it seems as though your float valve may be sticking. Did you put the float valve spring clips on the needles and connect them to the float arms? The clip is necessary for good performance of the system; it uses the weight of the float to pull the needle down when the bowl needs fuel.

 

[warstoryz]

Re: Still Need your Help Please

Thank you all very much for your suggestions. I really appreciate it and hopefully I can do the same for someone else one day. I will try all the different ideas, even those I have tried once before just to make sure I didn't dream doing it. <smile> I'll get back to everyone after I have done everything on the new check list. In the meantime, if anyone has anything else they think I should check or try, please don't hesitate to let me know. Thank you all again and good boating, John

 

[Solittle]

Re: Still Need your Help Please

The quickest (and best) way to start checking the electrical system is to make/buy a spark testor and check the spark to each cyl.

Your symptoms also point to crud in the carbs.