Fuel issues with Merc 50hp - need hints please

[bdm56]

BilgeBoy
just rewired entire boat, new battery connections to motor clean, new plugs from merc dealer, coils - hmmm, 3 of em and motor is still very smooth running when problem is present.

Keep coming back to fuel system cause problem is like it's starving for juice but only at times.

Don't know much about stator assembly, maybe a prob with it ?

[Angla]

Nuffy, Definitely look at electrical connections. Could also be a cable working its way out of a crimp or a connector with a pin pulling out the back. So a little pull on cables would be a good test. If it is a big earthing cable, give a good pull but if they are smaller cables just remember to use a little less weight.

Chris

PS. sorry no thoughts for your problem bdm56

[nuffy]

thanks megsy for your offer.Chris have checked all the wiring and conections its a manual 50 no trim tilt or elec start, so shes pretty basic, all looks ok, i thought that to,something earthing out but you can be going flat out and all of a sudden it feels like its dropped 2 cylinders and then othertimes it just hiccups.its a weird one and frustrating im looking out past flat rock this am and its like oil.

[PADDLES]

i'm clutching at straws here guys but some of the more common carby problems with 2s bikes are float and needle/seat valve related. is your float level ok? have you tried something as simple as raising the float level to get a little bit more fuel in the bowl?

[nuffy]

yeah paddles have looked at all avenues with carby and the strangest thing went for a run today and couldnt get it to play up keep my fingers crossed when i go again tomorrow but these things dont fix themselves.

[bdm56]

Spoke with an outboard mechanic today recommended by a mate and he reckons it will definitly be the stator or coil packs.

Will let you know when I have investigated these.

[James_Thorne]

bdm56

I had a similar problem with my 40hp 2st and no one could find the problem. fuel seamed to starve the motor sometimes, yet on other occasions seemed to flood the motor, and bulb would not go hard on pumping sometimes.

Bigest difficulty was that it was intermitent. I ended up taking the carby off, stripping the float shamber down, disconecting the float from the pivot pin, removing the needle that slides into the fuel cut out chamber, geting hold of a jewlers eye magnifying glass and having a good look.

Low and behold I found a tiny egg shaped bur stuck in a slight indent in the chamber. Seems to me that intermitently the bur would roll longways and push the valve needle over slightly to one side not allowing full closure of the needle point up into the seat. As the bur was an odd shape it would vary the seating of the needle. I had to actualy remove the bur using a needle as it seemed to have some magnetic hold onto the side of the needle chamber.

I think the mechanics trying to find the problem may have used air blast to clean it out, this rolled the bur and it worked OK again. And, as it was intermitent, no one looked close enough.

Anyway, problem solved and have had hassle free boating ever since.

Sometimes you just have to do it yourself, and sounds as though you know what your doing.

Hope you get it soughted soon.

Norwestjimbo

[bdm56]

For anyone following this thread just wanted to give an update and a warning. Never trust someone else to work on your motor if you can do it yourself >

Found my problem and it wasn't fuel. Gave the machine to a "reputable" marine shop in the Springwood area to have a solenoid replaced quite a while back and inspected the job briefly on return with no apparent issues.

Yeah well, whoever did the work actually crushed 2 of the wires which go to the CDI unit when wielding a spanner to replace the soleniod. Not much, just enough to split the plastic right up against the male & female connectors and at the rear out of sight.

Didn't notice this on careful examination of the exterior surfaces when my problem surfaced a while later but went to disconnect and clean every connection and in doing so noticed blackening and heat effects on the other wise soft, new looking wires and connectors on the hidden side. Obviously under some conditions an electrical "leak" was happening between the 2 wires. Guess I'm lucky, the CDI doesn't appear to have been damaged and after a careful repair I ran the motor on the water for 4 hours today without a problem.

Sloppy mongels > I am not even going to go near them again as I even discovered 1 of the earth leads to the new solenoid finger tight as well >

Have bought a workshop manual and will do all service myself from now on

And thanks to everyone who gave their 2 bits worth to this one

[Reef_fisher]

glad to hear you got it fixed. i had a similar problem with my merc 3cyl 50hp. i was about to suggest cdi. you symptoms were exactly the same as mine. everything that happened was intermittant like yous. the cause showed itself when i did a maintenance run to keep engine in good nick(hadn't used it for a while, anyway, started engine, noticed small amount of smoke coming from where smoke shouldn't. turned out the cdi caught fire. the gunk that they filled it with had split or been damaged some how and the heat did the rest. damn glad i wasn't 30ks out on the reef. mucho dollars later all niggly probs gone, must have been shorting when hot.

[plat-a-puss]

g,day nuffy i have a 04 merc 50 2stroke your prob sounds a little like a prob i had .i do a lot of trolling and on the last outting i found motor wouldnt idle but went great at wot . after a little time motor cleared itself and went fine ,did notice it was a lil smokey . sent motor in 4 service and chatted to mechanic bout problem he said stale fuel (fuel goes off quick these days ,so they tell me) and cause i troll the motor carbons up(causing the smoke).he put a carbon cleaning kit (bout $30) threw motor done usual 200hr service boat has no problems at all now ,no smoke ,idles great
so my advice would b do a carbon clean ,new plugs ,and dont use old fuel