1986 Mariner 90 hp outboard won't stay running when put in ocean?

[soulriderleo]

So, I took my boat out for the first time yesterday after putting it all together and boy was it an adventure!! Luckily I had my 1959 Evinrude kicker motor to get us back in. To make a long story short, my 1986 90hp Mariner outboard started and ran, but did not want to idle very well after it was warmed up. It also died almost every time I stuck it in gear? I finagled it to the point of getting it to get up and go, it went for about 1 minute at med & full throttle, then slowly died. It seams as if when in the water, the resistance kept it from idling or staying running when engaged in gear? After starting it and using the throttle to rev it up, I had to quickly throw it in gear and punch it to get it going? That only worked a few times, so I gave up and went it and called it quits for the day, as it was only a trial run to see how it would work the first time in?
So, after I got home, while flushing it, it started right up, idled, and went in gear with throttle up just fine?? So it feels like when submerged in the ocean, it is suffocating it to not run well??
Any ideas??
Thanks!!

 

[soulriderleo]

Re: 1986 Mariner 90 hp outboard won't stay running when put in ocean?

So, nobody has any advice? Could it just be carburetor adjustments that are not right causing the engine not to idle or stay running under load? Works fine out of water when hooked up to flush kit?
Any help, please!
Thanks

 

[Dave1027]

Re: 1986 Mariner 90 hp outboard won't stay running when put in ocean?

I'd try opening the idle mixture screws a little bit first. Might be something as simple as that. After that, carb and fuel pump rebuild.

Also, maybe the idle timing is set too low. That could make it die if the idle rpms are too low.

 

[soulriderleo]

Re: 1986 Mariner 90 hp outboard won't stay running when put in ocean?

Thanks!!

 

[MH Hawker]

Re: 1986 Mariner 90 hp outboard won't stay running when put in ocean?

Their is a difference from running on muff to running in water, its called back pressure and once it is in the water it needs to be tuned to run correctly, that's by adjusting the idle mixture and carbs and idle as per the manual.

 

[1nebel0]

Re: 1986 Mariner 90 hp outboard won't stay running when put in ocean?

Idle is adjusted by idle timing...very simple to increase the timing to speed up the idle as backpressure in the water will cause it to idle lower than on the hose....I have a 90h.p and the three cylinders motors don't idle that well on a good day.. I put my mini boat in the water in gear and adjust each idle mixture for best idle...then readjust the idle timing to meet spec's so it doesn't slam into gear..starting the motor and slamming into gear is going to cost you a lower unit very quickly....get her fixed.......