1986 Mariner 6cyl. 3 carb, carb problem?

JRBTS · #1 July 1st, 2002, 07:20 AM

I have a 1986 90Hp, 6 cyl. 3 carb mariner outboard

Has ran great last ten years I have owned it

Yesterday was first I launced the boat this year.

Starts and idles Great, But when underway about 1/8 throttle starts chocking but never stalls

Full throttle runs maybe 10 maybe 11 MPH chocking all the time. When I give it throttle with out gears engaged it roars (never misses).

Changed filter, plugs, fresher gas, same problem

almost like water in carbs.

Winterized the same way last year as I aways do

Ran out of gas, fogged, covered and put away covered

Any ideas

JB · #2 July 1st, 2002, 10:06 AM

Howdy, JR.

What happens if you pump your primer, choke it or squirt some fuel mix into the carbs?

Starts running? Check and overhaul your fuel pump.

Good luck.

JRBTS · #3 July 1st, 2002, 10:40 AM

Fuel pump is what I was thinking also, I pumped the primer and it didn't affect it either way.

Thanks

JR

JB · #4 July 1st, 2002, 01:30 PM

Howdy, JR.

If priming it doesn't help you probably have lost spark to several cyloinders.

To find the dead cylinders, disable each spark plug while at idle. No drop in rpm, no power, dead cylinder. Check the spark on each dead cylinder by holding the plug against the bloce and turning the engine over. You need a hot, blue spark.

Let us know what you find.

JRBTS · #5 July 1st, 2002, 01:44 PM

I'll try that this evening, Thanks

If a cylinder was dead wouldn't it miss at idle also? Idle and throttle up (no gears engaged) has no miss and revs very nicely

Your help is greatly appreciated

Thanks

Jrbts

JB · #6 July 1st, 2002, 03:59 PM

Howdy, JR.

The biggest liar in the world is a V6 2 stroke idling on 3 or 4 cylinders. The only way to know for sure is to kill each one and watch for rpm drop. No drop, no power.

Good luck.

MURX · #7 July 1st, 2002, 04:51 PM

if it sounds normal and revs up fine under no load (neutral) it's a switchbox

Bob Blair · #8 July 22nd, 2002, 06:30 AM

I know you mentioned its gone to the shop.

But, my 3 cyl. 90 HP that was doing as your is has been fixed. I rebuilt the carbs last saturday and its running just fine now. It was a bear to get them out. The bottom carb had old jelly like fuel in it and the main jet was frozen in place. I cleaned it up and all is well.