99 merc 4 stroke 50hp Has a lugi stuck in its throte

[jgogo]

here is my problem... my motor seems to lose power... it seems as though it has a lungie in its throte! last year i rebuilt the carbs after this problem ( a suggestion from a machanic) this seemed to do the trick the motor never ran better... but last week it happened again ( the lugie came back) for about a minute then the motor powered up again and ran fine ( hacKed up the lugie) So 5dayz later im back out and my buddy sayz my boat seems to be running great we bounce of a few big wakes and the we lose power.... shall i rebiuld the carbs again???? is this going to be a yearly job???? could it be something elce besides the carbs? Dashpot????

 

[Wingedwheel]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

I would look and see if you've got a loose or bare wire grounding out. You might have moved it when you rebuilt your carbs and it finally worked its way back when you hit the waves.

 

[jgogo]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

could not find any wires that looked abused

 

[Wingedwheel]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

Might not look abused, could just be loose enough to lose contact occasionally

 

[jgogo]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

went over everything today.. still no grounding problems.... think i should just clean the carbs???? continuos wave disscusses this problem a lil more and it seems cleaning the carbs is a ritual with these motors.... what do ya think...

 

[SeaKaye12]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

Hi,

I've been following your thread and I am surprised that none of the experts have suggested ignition failure. I read post after post of issues like yours where the spark cuts out on 2 of 4 cylinders and causes symptoms like yours.

If I were you I'd be thinking about how you could tell if all your cylinders are getting spark when the loss of power occurs. But; I'm not a mechanic.

Of course; you found last season that cleaning the carbs fixed the problem...so I suppose it wouldn't hurt to do that again.

Good luck, Chuck

 

[jgogo]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

im still in the midst of recieving new spark plg wires, fuel filter, and have the carbs torn apart in a ultrasonic cleaner. what would you think of aborting the inboard fuel tank. I want to run off a portable 5 gallon tank, that i can fit in one of my hatches. i feel that the inboard may have a ton of sediment in it (it is 25gal) but i dont even burn 25 gal in a season! im thinkin that the portable may be a better way this way i burn fresh fuel and can clean tank... by the way when i broke the carbs down there was a ton of crap in them... within 20 hrs of last carb rebuild last year!

 

[BassnKY]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

Just a thought... Do you have an in-line filter. If there is gunk in the tank, at least this would help keep the carbs clean.

 

[Reloder]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

I have the same engine and was considering rebuilding the carbs on mine. Did you buy a rebuild/repair kit for each carb or just the gaskets and clean whatever is necessary?

 

[jgogo]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

i do have an inline filter but, iwas considering putting in another would this restrict the flow? The first time i cleaned the carbs i bought four carb rebuild kits at 65.00 each they come with everything! floats, pins, gaskets, orings, .......

 

[ENSIGN]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

If you're using the gray mercury fuel line it seperates on the inside and clogges just about everything up.So far this year I've had four different boats with this problem.No help from mercury of course.

 

[BassnKY]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

Since you said that you have an in line fuel filter, is it getting clogged? If not, I would not think the gunk is coming from the tank.

definitely check out what jgogo mentioned. The gunk might be coming from the line after the filter. The ethanol in today's gas is not good on the fuel lines.

 

[jgogo]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

i do have the grey fuel line but, i kind of elimiated that being a problem seeing that the end that connects to the motor seemed clean and not deteriorated, but new lines wouldnt hurt while im at it isnt there some sort of ethonol rated gas line any suggestion on what type of fuel line and would 2 inlines restict my flow of fuel... as it stands all my filters are pretty new i replaced the last one12 hrs ago of motor use! mabe i could put one inbetween the tank and the fuel and water seperator??????? im gonna put all new filters after this carb cleaning....

 

[jgogo]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

i can easily replace the lines from the motor to the filter but, filter back is vert impossibe without cutting open the deck! there is no access!

 

[BassnKY]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

Your previous post gave me a thought. Have you checked the water separator. One way to check the fuel tank would be to siphon some fuel out making sure to have the PU at the bottom of the tank.

 

[jgogo]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

siphoned some fuel from the tank (a poland spring bottle worth) it was clean.... though you could see the blurbs from the quick clean.... i also have an aluminum tank so deterioration is not an issue like a plastic tank...

 

[jgogo]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

ok new spark plugs wires, rebuilt carbs, new fuel line, new fuel filter, new in line, going to load test now............ results soon to come!

 

[jgogo]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

all good!!!!!!!!!!!!!!!! the merc 50 hp 4 stroke is running like a top!!!!!!!

 

[waterinthefuel]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

It gives me a warm and fuzzy feeling when troubleshooting threads turn out so good.

 

[CharlieB]

Re: 99 merc 4 stroke 50hp Has a lugi stuck in its throte

You need to get back into that tank.

Alcohol in the fuel also means water, in the alcohol and in the fuel. Water in ANY METAL tank causes deterioration of the tank BOTTOM.

Hit a couple of wave, stir up the crud, pass thru cheap filters that are not near fine enough, then the carbs start accumulating crud, restricting fuel flow until.......................

either you notice..............

OR

you melt down the motor.

You say you pulled a CLEAN fuel sample, O.K. But did you remove the fuel level sender and stick a hose down to the BOTTOM of the tank to get that sample? I doubt it, cause that's a pain to do, but necessary to get to the root of your problem.

Ideally, with the boat on a trailer, jack and block one side to tilt the boat such that the fuel sender is on the low side. Just make double sure that the fuel level is down low enough that you don't create a massive spill when you unscrew the sender!!!!!!

If your sample off the bottom shows muck or water, keep sucking it out till it clears , pulling the muck out from under the fuel.

If you do not have a water separating filter then I highly recommend that you install one.