Outboard Diagnosis

Red Beard · Post by **Red Beard** » April 12th, 2020, 2:53 pm

Past couple times I took the skiff out, my two stroke mercury started dying at full throttle just about the time I get on plane. Few seconds or so.

As soon as this happened i would reach back and give the fuel bulb a squeeze. Bulb would be firm and tank vent open, and motor would still die off. No fuel leaked out while squeezing, so I assumed not a fuel issue.

Idled fine and would run up to half throttle fine. Until last night while gigging noticed the outboard sounded weak like all cylinders weren’t firing. Proceeding to gig on and not worry about it.

Rinsed and flushed the motor this morning and she cranked up still sounding weak, and eventually died off without wanting to fire back up.

I replaced the spark plugs this morning (no real signs of ware some carbon build up) and she fired right up with some authority, not misfiring or weak. But noticed my ignition cables are a bit worn and falling apart at the boot, so I used some electric tape to keep them from grounding and causing an arc for now.

Am I right in diagnosing this as an electrical issue?
And how do I go about finding replacement cables or making my own for this 1990 Mercury? The cables have a boot on one end and a bell shape connector on the other, appear to be around 18” in length or so.

I’ve tried placing my Googles on but can’t find what I believe I’m looking for.

Thank y’all ahead of time.
Happy Easter

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Post by **DixieReb** » April 12th, 2020, 4:31 pm

Replace the ignition cables, that could be part of the problem. I'd also mix some fresh non-ethanol gas with sea-foam mixed 1 oz. per gallon. You can mix it richer if you want, it won't hurt the motor. If it doesn't run better, your carbs could need some adjustment. Another thing I'd check is your fuel filter, it could need replacing. Good luck with it.

Red Beard · Post by **Red Beard** » April 12th, 2020, 4:39 pm

DixieReb wrote:Replace the ignition cables, that could be part of the problem. I'd also mix some fresh non-ethanol gas with sea-foam mixed 1 oz. per gallon. You can mix it richer if you want, it won't hurt the motor. If it doesn't run better, your carbs could need some adjustment. Another thing I'd check is your fuel filter, it could need replacing. Good luck with it.

Good points sir. I always run marine grade and add sea foam. And carburetors were just cleaned, but I’m not afraid to take them back off and clean again.

But I did not think to go ahead and replace the fuel filter while I have the cowl off.

These are the two end caps the cables have.

Post by **DixieReb** » April 12th, 2020, 6:40 pm

It could have been those plugs you changed, they do go bad sometime. Where I work we have an LE boat to patrol the lake on site. It was skipping, running bad, and finally quit cranking altogether. We did some things to it and finally changed both plugs. It cranked right up and ran after that.

Red Beard · Post by **Red Beard** » April 12th, 2020, 6:44 pm

DixieReb wrote:It could have been those plugs you changed, they do go bad sometime. Where I work we have an LE boat to patrol the lake on site. It was skipping, running bad, and finally quit cranking altogether. We did some things to it and finally changed both plugs. It cranked right up and ran after that.

Tenfo. Thank you for the feedback. Nice to bounce ideas off the forum before I think I know what I’m doing and have to pay one who does.

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Post by **Steve Stinson** » April 13th, 2020, 11:06 am

If you replaced NGK plugs with Champions, put the NGK's back in. Mercury outboards do not like Champion spark plugs. Crank the motor back up on the hose and WITH RUBBER BOOTS AND AND RUBBER HANDLED PLIERS pull one plug wire at a time then replace it. If the motor sound does not change, that cylinder is not firing. (I am not yelling at you here, just stressing the importance of the items listed

).

More than likely, if it's not the plugs or plug wires you have a power pak that has gone bad.

Normally when dealing with a fuel starvation problem or water in the fuel, the motor will slow down and speed up as it gets fuel, then starves. If you don't have a lot of surging going on it is probably an electrical problem. To diagnose a fuel problem, get a clean 6 gallon tank with a new hose and primer ball. Set it on the back deck of the boat, put some non-ethanol fuel in it and plug the fuel line directly into the motor bypassing your existing tank, fuel lines and water separator. If the boat runs fine on the portable tank, you have a fuel system problem.

Good Luck -
Steve Stinson

Red Beard · Post by **Red Beard** » April 13th, 2020, 1:16 pm

Thanks Steve I picked up on the rubber handles pliers. Lol

I hooked her up to the hose this morning, she fired up and than died after a few minutes of idling. Not a fuel issue dying sounds, just a drop of power and wouldn’t start up unless holding in the choke and giving some throttle.

Took the carbs off and cleaned just to check the box. Hooked back up, fired up and quickly died again. Getting plenty of gas and carbs did not appear clogged and dirty. Gas in van is brand new ethanol free mixed to 50:1 with oil and some sea foam additive.

The old spark plugs were NGK and that’s what I replaced them with. Thank you for that recommendation and insight.

Going to replace the boots and ignition wire, try it again. If no go than check the power pack I reckon.

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Post by **Fish Masterson** » April 13th, 2020, 1:31 pm

I would try a different tank and hose before digging into the power pack. I'm sure you could borrow one for a quick test.

Red Beard · Post by **Red Beard** » April 13th, 2020, 1:44 pm

Fish Masterson wrote:I would try a different tank and hose before digging into the power pack. I'm sure you could borrow one for a quick test.

Read my mind, I switched over to another tank. Same issue will not fire up unless I engage the choke, dies. And than will fire up burn the little bit of fuel and dies off again.

I’m getting a bit beyond my know how, may take it to Woodville. And let them tinker, I have a back up boat itching to get back the starting position.

Until it’s worked out.

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Red Beard · Post by **Red Beard** » April 13th, 2020, 2:44 pm

Dropped it off at my mechanic. Going to let him tinker with it. I will post an update on what the issue is/was.

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leonreno · Post by **leonreno** » April 13th, 2020, 8:29 pm

If it has the original or even older fuel lines could be they are deteriorating on the inside and clogging the fuel line, fuel filter or carbs/injectors. If it’s a carb model, cleaning and checking carbs would be my first thing to do. Otherwise could be stator or regulator too.

Red Beard · Post by **Red Beard** » April 15th, 2020, 4:38 pm

Alright guys and dolls got the grey ghost back from the mechanic. He applauded my efforts on cleaning the carbs, and than showed me the water he removed from my gas tank, floating in the bottom of a mason jar.

He said after he got the water out my gas, and adjusted the carb she ran fine. (where I had it out of wack putting it back together and didn’t take note of the setting beforehand)

I looked him dead in the eye and said, “so your telling me, outboards don’t run on water?” He laughed and said if I had any that did he’d take two. And we shared a laugh as he asked why I hadn’t installed a fuel/water separator on my skiff yet. (I’d gotten away without one until now)

I gave him some smoked fish/blue crab dip for taking care of me and thanked him again for his time.

I drove back pondering how water in got in my fuel and all I can think of is I got a bad batch of fuel.

I’m installing the filter this week and new fuel line before I do anything. And will go from there, still want to replace the ignition wires; don’t like tape keeping them together.

I’ll take my time and start at the simplest of things and install the device used to prevent such an issue.

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Post by **DixieReb** » April 15th, 2020, 7:25 pm

Well, well. I thought it sounded like it was starved for fuel, seen small 2-cycle engines do the same thing and small adjustment clears it up. But how in the world did the water get in the fuel?

Glad he got you going again.

Red Beard · Post by **Red Beard** » April 15th, 2020, 8:10 pm

DixieReb wrote:Well, well. I thought it sounded like it was starved for fuel, seen small 2-cycle engines do the same thing and small adjustment clears it up. But how in the world did the water get in the fuel? Glad he got you going again.

Your right you did mention fresh fuel.

Still scratching my head about how I got water in the gas. I know all gas has some water content, and aware of condensation’s effects. But no way i had as much water as I did without me getting a bad batch from the pump.

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Post by **onefishtwofish** » April 15th, 2020, 8:41 pm

Did it sit up for any length of time over the cooler weather with a less than full tank? I have been told that the warm cold cycles can condense the water vapor in the tank as a possible source of water in the tank. Sounds like you had a lot more than that though.

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