90hp johnson starting fault after road trip

Hi, I have an annoying problem with my 90hp 1998 johnson V4, if anyone can help?
The engine will normally start on the driveway, usual choke action works well, engine settles to idle nicely, I ve in Australia and ambient temperatures are 25C upwards, so no cold starting.
After a road journey to the boat ramp usually 25kms, the engine refuses to run, this usually takes place one in the water and in everybodies way.
The engine turns over correctly, and the engine sounds as though it's started , but dies immediately upon releasing the start key, for the next 20 mins or so this will be the case, Turn the key short rasp fom the engine, bit of smoke then silence.
Removal of spark plugs shows they are wet, but not oily.
At some point the engine wil fire up correctly and run perfectly the rest of the day, never missing a beat, even after an hour of more turned off.
Once the engine does start, it is immediate, without hestitation, which is leading me to believe it is and electrical problem.
When the engine is starting OK, it is faultless for an old unit, plenty of power, no miss fires, even trolling for 2 hours at 2000rpm gives it no dramas, just this issue of starting.
yesterday it wouldn't start as usuall on the water, then ran all day, at all rev's, took a short 65kms trip home, and it wouldn't start again.
any got and clues?? I did verbally threaten to sink the damn thing yesterday, and it started up immediately!

Re: 90hp johnson starting fault after road trip

That is a looper engine. The cranking speed is critical for it to start. If the cranking speed doesn't get to a certain rpm, it doesn't produce enough juice to fire the coils. You are probably right at the breaking point and one plug is trying to fire. Usually if one fires, it will kick the engine up a notch and the rest will then ignite. Once you get it started, the engine is warn along with all the components and it starts fine after that. Check all battery connections and clean them. Also check voltage at the starter and make sure you have at least 9.5 when the engine is cranking. Be sure to check the ground cables also.

Re: 90hp johnson starting fault after road trip

agreed. the drive may be shaking stuff loose; a very frequent cause of dozens of problems is the ground battery connection not being pliers tight. The wing nuts are a dirty trick.
Check all other connections, too.

Test your voltage both on the battery terminals and at the solonoid.

"Cold starting" problems often have nothing to do with air temp but just that the motor hasn't run for a while.

And then there's the illogical. I have a Yam 50 that won't start for the first time unless it is tilted all the way down. My Johnson will start out of the water (don't ask).

Or the Coriollis effect. Do your props spin backwards down there like your toilets do?

Re: 90hp johnson starting fault after road trip

Dave, That motor probably has battery voltage to the powerpack during cranking, so I do not think the cranking speed is the issue. I have a similar issue on my '98 Johnny 150HPV6. She will start and run perfectly. I stop at the beach for a while and when I go to restart, she will catch and die, repeatly.

If this was a late model car, I would suspect the engine temp sensor for the fuel injection is giving the wrong voltage. Of course the OBs do not have that. Try starting in the throttle-only mode at the lake, with the throttle advanced by an inch. Let her run at 1500 RPM or so for 30 sec and see if she behaves better. That works pretty well for me.