1987 115 Mariner

[Bassgod]

I am working on this motor for a friend and want some ideas to check out before taking it to the lake.
He tells me that this motor runs great for the first run of the day, everyday. After his initial run every time out, the next time he tries to go to another spot the motor seems to try and flood out. He said that if he just puts it in gear it will idle fine, but if he tries to give it some gas it acts like it will die.
He found that the lower plate of the powerhead cowling was loose and suspects water is getting inside and causing his problem maybe?? Could this be true and water is getting on the power pack and causing it to short out? Seems like a long shot to me.
My feelings is that it is a fuel problem, but I could sure use some more ideas. I am not looking forward to getting this thing stranded on the lake to troubleshoot. It is too cold for that!:$

 

[Laddies]

Re: 1987 115 Mariner

In most cases water won't bother the switch box (power pack) When the engine is warm and missing ck spark on all 6 cyls to see if it's a spark or fuel problem, I think it will be spark if you ck

 

[Bassgod]

Re: 1987 115 Mariner

Thanks Laddies, I believe you are going to be right. I just did my initial inspection and found no way water could get up on the switches anyway. All 6 plugs are in bad shape, so that is the first thing I am changing.
What would cause a loss of spark once the engine is warm, Stator?? Does this old motor have a high speed and a low speed stator?

 

[emckelvy]

Re: 1987 115 Mariner

Yup, this "new" would be distributorless (ADI) ignition and the stator, if original, would be highly suspect.

It'd be real interesting to measure hi and low speed stator winding resistances when cold; then again after running the engine and heating up electrical components to the point of failure. Bet you'd see quite a change from cold to hot.

I had an ADI stator last summer on a 115HP Merc that went from just-barely-out-of-spec on resistance, to "Shot" in a week, just sitting in my driveway in the hot sun!

This motor was cranky like your friend's motor, and I was lucky enough to be at the lake to experience the problem; smooth as silk at idle, ran great on throttle tip-in but fell flat on its face at around 2000 rpm.

Installed a new CDI-brand stator and it ran good as new.

At any rate, the resistance checks are easy enough; just make sure you have an accurate meter. If resistance values are even the slightest bit out-of-spec, the stator is most likely bad and should be replaced.

G'luck & let us know what you find..............ed

 

[Bassgod]

Re: 1987 115 Mariner

Thanks Ed. Do you know what color the wires are for the high and low speed stator? I have a great meter to use. Thanks for the info...Dustin

 

[Laddies]

Re: 1987 115 Mariner

Blue and Blue/white to = 5000-7000 OHMS
Red and Red/white to = 90 to 200 OHM
If you have a DVA it would be a better meter to test with, let us know

 

[Bassgod]

Re: 1987 115 Mariner

I can't believe I just found this website yesterday. You guys are great. I sure appreciate the support.
Ed, on the readings I need to take above, are those values what it should read cold, warm, or both? And I just measure bewteen the wires you listed above right? I am going to check these as soon as I get home from work.

 

[Laddies]

Re: 1987 115 Mariner

68 degrees, higher temps will increase readings slightly

 

[Bassgod]

STATOR CHECKS OK

STATOR CHECKS OK

Blue wire - 6.2K
Blue/White - 6.2 K
Red Wire -146
Red/White wire - 150

I opened up the fuel pump and found quite a bit of sand and grit. My plan of attack is to rebulid the fuel pump, replace his primer bulb, replace his water seperator filter, and change out the 6 old plugs.
Am I on the right track here or are there some other things I can check before going to the lake and freezing my tail off?
Thanks guys.
Dustin

 

[daveswaves]

Re: 1987 115 Mariner

I, sure laddies would agree, if there is sand and crap in the fuelpump it is certain to be in the carb bowls. It needs to have the carbs disassembled and cleaned (and carb kits depending on what you find).:/