mercury 135hp v6. running rough.. dying out.. carbs? help please

[dom_litty09]

i have a 17ft bass boat with a mercury 135hp v6, 2.0L. took it out today, after idling through a no wake zone i went to put the throttle down to take off, at full throttle it still wasnt getting up on plane.. i didnt look at the rpm but it didnt sound like it was even hitting 3000 at full throttle.. then when i backed off the throttle it died out and wouldnt start back up.. got it running again but im kinda worried about taking it out again.. theres not many boats out anymore so if my engine kills im pretty much stranded.. why would the engine be running like that? do the carbs need adjustment? the boat hasnt had an official run in about 4 years.. so im not sure where else to go from here.. any info would be great. thanks

 

[fisherman81654]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

Could be a lot of things since it has not ( had an official run in about 4 years)
My first guess would be fuel problem,bad gas,clogged fuel filter,clogged carbs,bad fuel pump,Try pumping the ball while tryings to get on plane,if that works replace fuel pump.

Take the cover off the carbs,Get someone to drive the boat and see if the carbs are sucking fuel in. if all are not working ,overhaul them.

If still same problem, check to see that you have good spark on all cylinders.

 

[Gierhedd75]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

Hi. I'm gonna give that a +1. Sounds like the carbs are probably all booged up with gunk and whatever else has been growing inside them and your fuel system for four years. I'd try giving them a good cleaning and new fuel to start. Also, check to make sure your ignition components aren't dry rotted or rusted over from sitting. I have the same motor. It's an 89. Just brought it back from the dead after the previous owner trailer sunk it and the boat on his front lawn for five years. Good luck.

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

thank you. im gonna take the carbs off today and clean them really good. i already put new gas in it, 93 octane (no ethanol). hopefully the carb cleaning will work, ill post again later today and let you know

 

[CharlieB]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

Also rebuild that fuel pump and replace all stiff hose and primer, any restriction in the fuel supply can cause the upper cyl to go lean and melt a piston.

Fuel pump kit, primer and hose can all be had quite a bit cheaper than a new piston.

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

i tore apart the carbs today.. they really werent all that dirty.. and the fuel pump looks pretty much new.. i just replaced the top left piston so i mixed the oil a little rich (the oil injection doesnt work). could the carbs just need a good tuning? also the guy i bought it from said the 88s are kinda dogs out of the hole, but when they get on plane they run like a champ. so im waiting on his call back right now to see if i gotta play with the trim to get it up on plane.. he said something about the trim before so maybe thats it

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

i know the carbs are running a little lean because when i had the motor tore down thats what my mechanic told me by the look on the pistons.. how do i tune these carbs? i have a book but it only has info on how to tune the single barrel carbs and i have 3 double barrel carbs.. is it hard to tune these? my dad knows alot about carbs but has never messed with anything like these.. or do i need to bring it to a mechanic to tune them?

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

sorry i meant they are running rich.. im gonna have my dad check them out tomorrow.. where are the screws that he would need to turn to make the adjustment on these carbs?

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

got the carbs all adjusted right.. then saw that the bottom carb was dumping gas.. the needle valve and seat are jammed up too high. so far we cant get it out.. where would i buy a new carb if i need one? serial number 0A362422

 

[Gierhedd75]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

Getting a replacement carb may be a feat, but I'd start by checking out CL or eBay. Have you tried soaking it for a day or so? Threads stuck? May want to look into letting the boat mechs take a whack at it. Good luck and keep us posted.

 

[Sprky]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

I have a set for the 135's if you can't fix yours.

What is stuck, the seat? If so, use a punch and hammer to loosen it.

 

[aussieflash]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

88s are dogs??Only if you don't look after it.Got the same motor and pushes my 1 ton ++ out of the water no problem.You need to adjust floats to 1.6mm.Replace all gaskets and needle/seat assemblies.then reset timing.Good Luck.

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

thats just what a mechanic has told me is that some of the 86-90s are dogs from a take off, but after that they run like champs. and i figured out that the seat for the fuel jet is too low, but i cant get the threads to let loose so i can adjust it. its so low that it is blocking off most of the fuel intake on that barrel, it still gets some, but not enough. i have it soaking in pb'laster right now hopefully that will loosen the threads. sprky - if this doesnt work how much would you sell the carbs for? or just the bottom one?

 

[Sprky]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

Take a pic of your problem and post it. I cannot figure out what your are dealing with.

I would only be interested in selling one carb if they are the same series as yours and I got yours in exchange.

$50 plus the ride.

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

well i was tired of messing with the carb and put it back on the motor.. and it worked fine. i think the fuel jet was clogged up. im gonna take it out here soon and see what it does. if not we can work something out with the carbs. ill post again later today

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

well bad news.. the carb is loading up on gas again and its flooding out and killing the engine. it idles fine but once you take off and get on plane it only goes about 10 seconds before it bogs out. were gonna have a buddy mechanic come down and check it out. not sure what to do with it

 

[CharlieB]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

That doesn't make sense.

A carb doesn't flood AND idle fine.

Running about 10 seconds WOT then bogging is often a sign of a restricted fuel supply, unable to flow enough fuel for sustained load.

Disconnect the fuel hose to each carb one at a time, crank the motor and watch for a strong pulsed flow. You may have one bad hose restricting one or more carbs, fuel pump, fuel tank fitting, something somewhere, limiting fuel flow.

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

well we figured out my fuel tank fitting was clogged so we switched to a different tank. and like i said it idles fine, but the one carb is slowly dripping gas. then at wot it kills out after about 10 seconds, i figured it was from the carb flooding. cause when we try and start it again it acts like it is flooded

 

[dom_litty09]

Re: mercury 135hp v6. running rough.. dying out.. carbs? help please

we have a mechanic friend making a house call to check it out on the water.. he said that it sounds like restriction somewhere also. could it be from a clogged fuel filter? it could pry use a new one..