1985 Johnson 115 hp Runs Great Then Will Not Run at High Speeds...

[ut_freak23]

I have a 1985 Johnson 115 SeaHorse. This motor has been stored for about 6 years. The motor is very clean. It was stored properly. Recently the boat was taken out of storage and this is what we have so far. We replaced the spark plugs, drained old fuel in tanks, new fuel lines, new fuel filter, and changed lower unit oil. The motor started after a couple of cranks on the water muffs. The water pump indicator shot water. We had no fuel leaks or water leaks. The motor idle very smooth no smoke. When the boat was taken out to the lake it ran like a champ for about 45 minutes. This is a bowfishing rig so we killed to motor to fish some. When we started back up it fired off no problem and idled great. When we started to head back to the dock the boat would rev up to speed but then die out or idle down. When the boat would die it would start right back up and idle but on full throttle the boat would reach high rpm then die again. We waited about a week and the boat did the exact same thing starts idles runs for about 45 min to 1 hour then we cant get the boat to run wide open. Any help in this area would be appreciated.

Thank You
Josh

 

[tashasdaddy]

Re: 1985 Johnson 115 hp Runs Great Then Will Not Run at High Speeds...

Welcome to i boats. #1 your a fool for running on a 6 years old impeller. check your compression and spark. also sound like a carb rebuild is in order. read this: http://forums.iboats.com/showthread.php?t=158086

 

[ut_freak23]

Re: 1985 Johnson 115 hp Runs Great Then Will Not Run at High Speeds...

I have been asking around for help and power packs were mentioned as a possible problem. How can I check these and would it be best to run the boat until the problems start happening or would the problem be evident from the start.

Thanks
Josh

 

[ut_freak23]

Re: 1985 Johnson 115 hp Runs Great Then Will Not Run at High Speeds...

New info...On the water flow indicator that shoots water out the disc shaped end was clogged. The end was cut off to see if water was flowing. Is this a crucial part to keep pressure in the water cooling system any info would be appreciated.
Thanks
Josh

 

[rob711]

Re: 1985 Johnson 115 hp Runs Great Then Will Not Run at High Speeds...

i'm having the same problem...try searching "what now" although the search engine here is ng....mine was sitting only 1 year..i changed plugs..rebuilt carbs...insulted its mother still havent remidied it..but!!! six years is a long time for your rubber impeller to be in the same position...unless u stoped by every six mounths and turned the motor over, u really should change it..u should have a steady constant stream of water comming out of that "tell-tale" or "pee-hole" all the time..what was it clogged with..hopefully not a piece of your impeller!!did it over heat i assume u had no alarms go off...u can check them buy grounding the sensor wire to the block w/the key on...they are the things in the top of the heads with the wires comming out..but i doubt u did from what u wrote..i'm going to order new powerpack 4 mine..its frustrating b/c not 100% sure thats the problem but ....hey its only money!! good luck there is a lot of helpful people here

 

[ut_freak23]

Re: 1985 Johnson 115 hp Runs Great Then Will Not Run at High Speeds...

This post is way overdue. I just wanted to say the problem on my buddies boat was the gas tanks. We hooked up two new tanks and the thing runs like a champ.

Thanks For All The Help,
Kaleb

 

[Barnacle_Bill]

Re: 1985 Johnson 115 hp Runs Great Then Will Not Run at High Speeds...

I hope you at least changed the impeller. They dry rot from sitting like that for that long.

 

[tbock]

Re: 1985 Johnson 115 hp Runs Great Then Will Not Run at High Speeds...

I have had simmilar issues with outboards not pumping enough oil at higher RPM and shutting down.
You start them back up again, and they run fine untill the rpm is back up, and they quit. ( Very tough on power heads).

Many profesional rebuilders will disconnect the VRO Pumps on the early oil injected models, for this reason, and warn buyers to run mixed gas only in them.
The old VRO Pumps are notorious for failures once they get old, and or have been stored for long periods of time.

Tbock.