85 johnson 140 v4 wont start after running for a while

[indyfiero]

Twice in the past two weeks this engine has left me stranded. The boat and motor are new to me and ive had it out 4 times total.

It has no problem starting cold and getting us up on plane and out on the lake. Then usually i shut it down, fish for a while and move to a new spot. The last two times out this starting and stopping seems to have killed the motor. I could crank and crank and crank and it wont fire. Once i get it home it fires right up. Homesick maybe?

Im wondering if its something im doing wrong. Sometimes if it doesnt catch on the first four or five cranks while warm ill push the primer in while cranking but i think thats just making the situation worse. Ive also tried raising the idle lever to see if that helps.

Any ideas?

 

[racerone]

Check / inspect the starter , battery and cables.--Do a compression test too.

 

[interalian]

What's your starting procedure when trying to get it going after fishing? Any priming? Raise idle? Or just crank in neutral with no idle boost? Sometimes you need to prime them again and treat like a cold start. Other times this floods them. Worth knowing.

 

[indyfiero]

Starter seems fine it cranks super fast. Comp is 125 on 3 cyl and 110 on another. The 110 cyl has a retapped spark plug hole with a thread saver insert and i think it loses a bit of compression because of that. Battery is brand new.

Hot start procedure is usually just to crank it in neutral till it starts. However if it doesnt catch after say 10 sec of cranking i usually try priming while cranking or raising the idle lever or both.

 

[BRBHorizon]

I have a 130HP but this sounds similar to my issue. Try priming before restarting, if that helps it could be your anti siphon valve. With (a lot of) help from this board (and others) I replaced my anti siphon valve as well the whole fuel line and primer bulb, and that helped. On another board, another suggestion was the stator may be suffering from the heat rising once the engine is stopped hot.

 

[jakedaawg]

Check for spark with an open air gap spark tester when you are experiencing the issue. As electrical parts get warm sometimes they fail.

 

[interalian]

Marginal parts can fail when heat soaked. After running the motor for a while at higher throttles then shutting down, the stator, timer base and flywheel all get quite hot. Heat can open circuits. Agree you need to test for spark when it isn't starting. A spark tester or a timing light clipped to one of the cables.

 

[indyfiero]

Thanks for the suggestions guys. I'll give that a try. Is it reasonable to assume that I can replicate this issue in my driveway? Let it run with the muffs on at WOT or near WOT using the idle lever and then shut it down after a few mins of running like that? I really don't want to be troubleshooting this out on the lake every time.

 

[interalian]

Do not, repeat: DO NOT run your motor in neutral at high RPMs. Please. You can grenade the motor.

To replicate heating issues, the motor would have to be run a very long time on muffs at idle for heat soak to become an issue. Motor makes the most heat under load, and when you shut it off after running under load, the heat will soak up into the top of the motor where the stator and timer are. Also, the heat will soak into the power packs.