Engine dies under load 1989 Johnson 115hp

[Rayhaley]

My engine dies while under pressure. It will get up on plane and run a minute or so and then act as if it is running out of gas and die. I don't need to pump the bulb to get it to restart. It will do that fine. I get the same thing over and over again. If I give it just a little throttle and chug along like a slug it will generally go fine. It also seems to take a lot of time to get up on plane. (That is when I'm able to get it to run long enough!)

I took it to the shop and just got it back a few days ago. The techs only did what I asked and didn't troubleshoot this problem. I asked for what I knew was bad and what I thought was bad.

New Fuel Pump
New Water Pump
New Water Wheel
Fresh Gas
New Fuel Filter
New Fuel Bulb and Line

Any ideas? I hate to keep sinking money into such an old boat but I can't justify a new one.

 

[Daviet]

Re: Engine dies under load 1989 Johnson 115hp

You need to do a couple of simple checks, spark and compression, to make sure all the cylinders will fire properly. What plugs are in the engine and what is their condition? If those check out ok, you need to move on to the carbs.
What is a water wheel?

 

[Rayhaley]

Re: Engine dies under load 1989 Johnson 115hp

the wheel inside the water pump that goes bad. i'll try your tips and see what happens. thanks!

 

[Bikeluver43]

Re: Engine dies under load 1989 Johnson 115hp

I'm having the same problem with my 70HP motor. I'm thinking the carbs have gunked up so I'm going to try to spray some cleaner through the fuel passages to see if that will clear it up, otherwise I'm planning carb rebuilds.

 

[Rayhaley]

Re: Engine dies under load 1989 Johnson 115hp

Unfortunately I'm not a mechanic. Not quite sure if I'm up for a carb rebuild. Good luck. Please post your results.

 

[emdsapmgr]

Re: Engine dies under load 1989 Johnson 115hp

All of your repair work is focused on the fuel delivery and cooling. Very possible that your engine is losing spark to one or more cyls. Weak ignition components tend to fail once the engine heats up to normal operating temps. An engine can seem to run/idle just fine when running on 2, 3 cyls. If you don't have good spark to all 4, it won't plane out properly. Get the engine fully warmed up, then check for spark on all 4 cyls. The cyl drop test works well, or use an inductive timing light to check spark quality.

 

[Rayhaley]

Re: Engine dies under load 1989 Johnson 115hp

Thank you so much for the suggestions. That will be my very next step. After that compression and carburetors. Hopefully I'll get it sorted out soon. Missing lots of fishing!

 

[Rayhaley]

Re: Engine dies under load 1989 Johnson 115hp

so i changed the plugs and did a spark test. cheched out fine. the original plugs were gapped too much. compression check yielded 90 lbs on each cylinder. my auto mechanic friend thinks it's an ignition system issue or some type of module. any ideas?

 

[emdsapmgr]

Re: Engine dies under load 1989 Johnson 115hp

Did you do a spark test once the engine was fully warmed up, and idling in gear at the dock. Putting the engine under a slight load is a good stress test for the ignition system.

 

[Rayhaley]

Re: Engine dies under load 1989 Johnson 115hp

No I didn't have the chance to drop it in the water yet. I hope to do that one day this week. I'll do a second spark test then. Who knows. Maybe I'll get lucky and new plugs properly gapped will do it. (Although I won't hold my breath.) I did however obtain a very noticeable increase in the idling rpm rate once I started it with the new plugs inserted. The old plugs were dirty and wet with oil. Is that a good or bad thing? The oil that is. Shouldn't the plugs be dry?

 

[emdsapmgr]

Re: Engine dies under load 1989 Johnson 115hp

On that two-stroke it's pretty common for the plugs to be wet an oily when idling. They will turn a nice light brown after running WOT for a short time.

 

[Rayhaley]

Re: Engine dies under load 1989 Johnson 115hp

Thanks for the information. I appreciate all of the help I can get!