Johnson 1970 115hp

[Davelin]

I have a 1970 Johnson 115 that hasn't run for about 5 yrs, and finally got it going and ran it for awhile today. It would restart very well after I turned it off, but when it sat for about an hour I could not get it to run again. It would fire, but would not continue to run. I have installed a new fuel pump and cleaned the carbs. The fuel tank is in the front of the boat and has a long fuel line that is very old, but I am able to pump it up OK.

Any thoughts would be greatly appreciated.
Thanks,
Dave

 

[Sander]

Re: Johnson 1970 115hp

Could be an ignition problem. You could do a few regular tests.

 

[ohioriverat]

Re: Johnson 1970 115hp

New pump deserves a new line, i had 2 mowers last week that would not run long cause they were collapsing the line. If it pumps up it should run for a minute on whats in the bowls, New plugs??
FFC fuel, fire ,compression, i start with new plugs always

 

[ADK_Boater]

Re: Johnson 1970 115hp

Sounds a little like a fuel delivery problem I had. Wasps build nests in the fuel connection fitting right at the motor (male end attached to motor). I also had a mud-wasp nest in the fuel line. I'm not saying it's wasps, but I would check all fuel lines for blockage/damage/defects first. If no luck, then start spending money on plugs etc.

 

[Sixmark]

Re: Johnson 1970 115hp

Did you take apart the carbs and clean them or just spray some cleaner in them?

How old is the fuel in the tank?

Try using a portable tank and running it and see if the problem persists, if it goes away then start by cleaning the onboard fuel tank and replacing the lines. If you didn't properly clean things in the first place then all you are doing is stirring up sediment and chunks of varnish and they will lodge themselves in other locations and create havoc.

 

[Davelin]

Re: Johnson 1970 115hp

Thanks for the response guys. I did clean the carb on the bench thoroughly, but I'm thinking that I will replace the needles and seats if I can't get it to run off a portable tank. Plugs are old as well and I will replace them.

Thanks again,

Dave

 

[Davelin]

Re: Johnson 1970 115hp

Today I replaced the needles, seats, plugs and fuel line. Engine started hard (Always has) but was able to get it to run for quite awhile in the driveway. I could also get the engine to rev OK in the driveway. Sooo, I took it down to the lake and got it running, but when I increased the throttle, the engine would begin to skip and then stall out. I could not get the engine to push the boat around with any gusto and seemed like the load was too much.

Thanks,

Dave

 

[Daviet]

Re: Johnson 1970 115hp

Preform a couple of simple tests, check the spark with a timing light to make sure you have spark at all cylinders. Have you run a compression test? Use a squirt bottle with fuel mixture in it and spray directly into the carb bores and see if it picks up.

 

[bigpoppakdog]

Re: Johnson 1970 115hp

My 1970 115 evinrude starts exceptionally easy on muffs in the driveway. I should suspect your motor should too. However, when I have messed with the idle screws(to get it just right) then I will have issues. Doesn't take but one of those needles to be open too far and I would have starting/idling issues. From the sounds of it, you are experience back pressure while your motor is in the water versus the driveway. If possible this is what I suggest. Back your boat down the ramp. Keep the tie down straps secure and keep it winched tight. Lower motor into the water. Make sure motor is in idle. Close all 4 slow speed mixture screws. Then open all 4 of them 7/8 of a turn. Throttle to "start" position and attempt to start. Once started and warm, throttle down into low and put into forward. You now can adjust the screws to achieve best rpm. If in neutral with throttle at low and your engine dies, adjust the idle screw a few turns. This will bring the rpm's up. This has been the best way for me to adjust the fuel mixture by myself. I don't need a driver and I don't need to be leaning over a spinning flywheel while the boat is moving either. Also, not sure if that motor has it, but if you have that linkage system on those 4 screws, order the o-ring inserts for it and throw that linkage system away. Virtually impossible to adjust things and get that damn linkage system back on without screwing everything up.

 

[Davelin]

Re: Johnson 1970 115hp

OK...here is where I am at. Regapped my plugs and checked to make sure each cylinder was firing with a timing light. Took the carbs off again and did some more cleaning. Boat started real well and idled much better and actually was able to get it up to full throttle today (after some hesitation) and ran some circles around the lake (Not getting too far from the boat ramp however). It felt like the old days so I got cocky, and shut her down. The motor started right up, but I could not get wide open again and engine would stall. We tried to spray fuel into the carbs, but that didn't help at all. The motor starts right up every time now, and will hit a fair cruise speed, but still stalls when I goose it. I know things are getting better and it was fun for the 15 minutes we were speeding around. What would cause it do this after it worked fine for awhile? Is it overheating?

Thanks,

Dave

 

[Daviet]

Re: Johnson 1970 115hp

Did you do a link & synk, got a factory manual?

 

[Davelin]

Re: Johnson 1970 115hp

I do not have a manual. Not sure what that is exactly, although I have an idea. It must be like my old MG carbs that needed to be syncronized from time to time. Is the info anywhere on this forum?

Thanks,

Dave