Please help with Johnson 115 powershift

I have a 1974 115hp Johnson that is giving me fits. It will run fine on muffs (sometimes) but it is very irratic. I put a new power pack on it and it seemed to run good so we took it out today. Put it in the water it started right up, idled out to open water and came right up on plane and seemed to run well for 10 to 15 minutes then died when I throttled back. Took forever to get it to run well enough to get in gear and go, I had to play with the choke to keep it going then it took off untill I throttled back again to go to the ramps. Now it wont idle without being a super high idle and it sounds like its only running on half the cylinders at lower RPM but if you bring the RPM up it smooths out. The carbs have been gone through, it seems to be getting plenty of gas since it started to puddle under the front of the motor, I assume from choking the crap out of it to keep it going. Pulled the plugs out and check spark on all 4 cylinders and they all have good spark. I checked resistance on the trigger and it is within specs. I dont have a DVA to check the stator but from what I have read I dont think that would be the problem. Any help wold be greatly appriciated!

Re: Please help with Johnson 115 powershift

Have you had the flywheel off, and if so was it torqued to 105 FT LBS when replaced?

How many wires run to the choke solenoid, and to what do they connect?

Pull the drain plugs on the carburetor float bowls one at a time and squeeze the bulb to flush the bowls. The high speed jets are behind the drain plugs at the bottom of the bowl where they pick up all the junk AND WATER.

Do you have a water separating fuel filter?

Re: Please help with Johnson 115 powershift

I did remove the jet plugs and fuel flowed out like it was ok. There is 1 wire to the choke solenoid, it runes to a power strip if you want to call it that. I just have a stock type filter but there doesnt apear to be and water in the gas. I checked compression also and it is 120 psi on all 4.

Re: Please help with Johnson 115 powershift

If you have good spark and compression, you should focus on the fuel supply; if you did not install new kits and gaskets on the carburetors you might want to consider doing that.

Re: Please help with Johnson 115 powershift

I pulled plug wires one at a time with it running and there is no change with cylinders 1 and 2 but 3 and 4 kill the motor if pulled. The top carb supplies the top 2 cyliners correct?


If it was the trigger (timer base) it would be 1 and 3 or 2 and 4 correct?

** Checked voltages on trigger(timer base) and stator when cranking and they all seem in spec.**

Re: Please help with Johnson 115 powershift

If it were the trigger, it wouldn't have spec voltages. Also, it wouldn't have spark on those cylinders. Also, if it were the powerpack, it wouldn't have spark on those cylinders. Look elsewhere.

"Spark" means it will jump a 7/16" gap with ease.

Do you have the correct spark plugs? By "correct, I mean L77JC4 or QL77JC4, not hose crappy surface gap plugs)

Re: Please help with Johnson 115 powershift

Yes I have the correct plugs according to the sticker on the motor. I checked with a spark gap tester and have sufficient 7/16" gap spark.

when I pulled the wires you can hear the spark jumping to the plug when you get it near, but pull it back away so no spark jumps it still make no difference in RPM

Re: Please help with Johnson 115 powershift

From your prior post, sounds like 1 and 2 are dead cylinders. 3 and 4 ok. Either they are not fueling properly, or they have no spark. If the plugs are wet, likely no spark. An inductive timing light will verify spark. If the plugs are dry, likely a fueling problem with the top carb. You may have to pull the carb apart.

Re: Please help with Johnson 115 powershift

Yes 1 and 2 are the dead cylinders. They have spark, you can see it jumping when you pull the wire off. pull the plugs and they also have spark so Im assuming it is the top carb. I will pull it and go through it again. Thanks.

Re: Please help with Johnson 115 powershift

ok pulled the top carb and dissasebled and checked everything and blew air through all the passages. I didnt see anything out of the ordinary but when I put it back on and fired it up problem solved!! Must have had some dirt in it. Thanks to all you guys for the help!!