Fuel Issues , Hard To Start , Motor Keeps Dieing Out

[MikeCustomBaitPainter]

1988 Mariner 115HP In-line 6

Boat just doesn't want to idle , keeps shutting down , once it shuts down its hard to re-start. Took the crow off & everything is wet with gas ? I wiped everything down put the muffs on & started the motor looking for leaks ? I didn't see anything but notice a few things. (1) I placed my fingers under the top carb where the throttle shaft enters the bottom and it appears gas is leaking from under the carb ? (2) I did the same thing under the middle carb where the throttle shaft enters the bottom of that carb and it appears gas is leaking from under that one ? Does this make any sense ?????

Thanks For Any Help

Mike P.

 

[Chris1956]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Sounds like the carbs are flooding. When was the last time they were cleaned and rebuilt? Sounds like it may be time.

 

[MikeCustomBaitPainter]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Hey Chris ,

Maybe (3) yrs ?

Mike P.

 

[Chris1956]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Mike, The throttle plate rods are a snug fit in the carb throats, but is fuel leaks into the throats, it will drip as described. The cure is to replace the floats inlet needles and seats. Maybe they can just be adjusted to meet spec.?

 

[MikeCustomBaitPainter]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Hey Chris

I can see where the gas is leaking , its the front plug screws on (2) of the carbs, I guess the washers are bad. Here's my question , when the boat is under load , is this enough pressure to cause these issues from these leaks ? I'm going to rebuild the carb's anyway , just to make sure all is good.

Mike P.

 

[Chris1956]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Nah, Those shouldn't leak. Fuel pressure is real low..almost too low.

 

[MikeCustomBaitPainter]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

How are the upper & lower lever float pins removed ?

Mike P.

 

[Chris1956]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

They are press fit. They have a knurled end that fits snug into the cover casting. Why do you want to remove them?

 

[MikeCustomBaitPainter]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

I was going to rebuild the carb's , Don't I have to remove the float pins to remove the upper & lower levers , then I can replace the float inlet needles and seats ?

 

[Toddboat]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Stalling in idle is from clogged idle circuit in the carbs. Low speed jet is likely also clogged. Hard to restart is due to flooding from bad needle/seat. Start it hours later and it will start. Carb cleaning and rebuild should solve all problems you're describing. I recommend a carb bath for a couple days in addition to manual cleaning.

 

[MikeCustomBaitPainter]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Hey Guys

What size main jet will I need , The parts listing shows two standard sizes ? - 1399-3796 JET, MAIN FUEL (.076) (STANDARD - WMK-41B) & 1399-3794 JET, MAIN FUEL (.074) (STANDARD - WMK-41-A)

Can anyone tell me what #No's on the photo are my High & Low speed jets ? My manual doesn't say whats a High/Low speed jet ?

Thanks For You Help , Mike P.

 

[Chris1956]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Mike, Just clean all the jets. No need to replace them. Replacement parts are usually limited to floarts, inlet needle and seat and gaskets. Float levers are bent to adjust them. No usual need to remove them

 

[MikeCustomBaitPainter]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Ok ,

Everything done , Rebuilt fuel pump , replaced squeeze bulb , Re-built carbs , Started in driveway just fine. Took boat to lake , started fine , went to get on plane , motor just kinda bogged down , then got a burst of power & took off. Fished for about 45min , motor started fine & jumped on plane great , fished for another 45min , motor bogged again , got on plane real slow , once on plane rode for about 5min and then had another burst of power and took off at full speed ? What Gives Guys ?

Mike P.

 

[Chris1956]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

It is likely your idle mixtures are a bit lean. Open the top carb mixture screw 1/8 turn and retest acceleration. Repeat with mid carb and then bottom carb, testing after each adjustment.

 

[MikeCustomBaitPainter]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Chris ,

Your saying with the boat on the water , start with top carb 1/8 turn , if that works , leave the other carb's alone ? If not , Go to the next carb 1/8 turn & So on ?

Mike

 

[Chris1956]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Mike, That is exactly what I mean't. Good luck. It is a bit tedious, but effective.

 

[Silvertip]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

Dropping power and then a burst of power does not suggest carb adjustments. It suggests ignition issues. Check the spark plugs and replace them if necessary.

 

[MikeCustomBaitPainter]

Re: Fuel Issues , Hard To Start , Motor Keeps Dieing Out

My plugs are brand "New"

Mike P.