Mercury 1500 Carb Issues...

[Dellonn]

Okay, so here we go again.

Yesterday, I load up the wifey, the kids, the tube, the ski's etc. I run my boat for a good 90 minutes. Sure it's a bit rough at idle in the beginning, but soon i'm yanking skiiers out of their boots

So, after about 90 minutes of playing I park the boat at the dock and unload to eat some lunch. About an hour later, I come back and it's hard to start. It seems to stay flooded and there's fuel pouring out of a "pee hole/overflow?" in the top of the top carb. Is a float stuck?

I play with it for an hour or so trying to get it to run. I can't get it above 2k rpm, and won't idle at all now. I have new fuel tank, new fuel, and new fuel lines. I check for spark on 5 out of 6 cylinders and have no issue.

So, I'm guessing I need a carb rebuild (or three). Is this something I can do myself? If so, how do I sync them? I've done carb rebuilds before on multi-carb motorcycles and have never had much luck getting them to run smoothly. Any advice or suggestions? Which Carb Kit do I buy?

 

[Bondo]

Re: Mercury 1500 Carb Issues...

So, I'm guessing I need a carb rebuild (or three).

Ayuh,... I agree....

Is this something I can do myself?
I've done carb rebuilds before on multi-carb motorcycles and have never had much luck getting them to run smoothly.

Sounds like Probably not....

 

[Dellonn]

Re: Mercury 1500 Carb Issues...

Well, I was hoping that with the advice of the super knowledgeable, super dedicated friends here in iboats, I could be given that one tip, piece of advice or key insight that make rebuilding these carbs seem simple.

Either way, I'm going to attempt the carbs myself. I hope someone can steer me in the right direction.

Thanks in advance for your help.

 

[Dellonn]

Re: Mercury 1500 Carb Issues...

you guys are kinda quiet today. Help a guy out! hehe

 

[Chris1956]

Re: Mercury 1500 Carb Issues...

I would check the carbs again. Sometimes they get unstuck and work fine.

If not, get a gasket, inlet needle for each carb. First check the condition of the floats. The originals were foam, and tend to fall apart. Replacements were hard plastic and can crack. Check the little springs on top of each carb. Replace the floats as is necessary.

Remove, soak and clean each carb. Install the new inlet needles, gasket and seats. Set the float to spec (get a service manual) and install new gaskets. Set the Idle mixture needle to 1-1/2 turns from lightly seated. Install carbs.

Mix up fresh 50::1 gas oil mix. Drop boat into water and warm it up. Now idle in gear if possible while adjusting. Turn each needle a bit in each direction until you have maximized the speed and smoothness of the idle. Now try to accelerate. This mixture is usually too lean to accelerate smoothly, so open top carb 1/8 turn and try again. Follow with mid carb and then bottom carn, testing after each adjustment. Eventually you will find a reasonably good idle and smooth acceleration.