Engine Surging Question - 1985 85hp Force

[1NewBoatGuy]

OK, today I went to the lake and my motor would not stay running. I got home hooked up on the muffs and found some leaky gas lines so I replaced them. Then I cleaned out the carbs. According to the user manual that came with the motor it says when adjusting the carb mixture screws, to turn them out one full turn after screwing them all in. Then adjust out until the motor gallops, then screw in until it smooths out.. Currently the screws are all at about 1 1/4 turn out.
The problem I have is the engine seems like it's surging or stuttering. It seems to run fine for a few minutes then starts stuttering.

Compression on each cylinder is about 100 psi, I know this is low, but could this honestly be the real problem here?

I am suspecting an ignition system component but I am new to working with boat motors and really need a good diagnosis before I start dropping bills to by parts.

Boat has new fuel diaphragm, Impeller and Impeller housing as of two weeks ago.

PLEASE HELP!

Motor running on muffs

Boat running last weekend
http://youtu.be/gfTEf16j3g0

 

[foodfisher]

Re: Engine Surging Question - 1985 85hp Force

Fuel hoses and connections. Possible air leaking in.

 

[1NewBoatGuy]

Re: Engine Surging Question - 1985 85hp Force

That's what I thought, I replaced all hoses from pump all through carbs because they were all wet and when I would squeeze the fuel bulb they leaked, there all good and new now. Carb bowls stay full, really boggled here.

 

[jerryjerry05]

Re: Engine Surging Question - 1985 85hp Force

Are all 3 cyl at 100#?
Check for water in the gas.
Pull the diaphram and check(even though it's new).
All the nuts tight?
Take some starting fluid and spray around the different area of the motor and at the base of the carbs(not in the carbs).
See if the motor picks up or slows when spraying.
The carbs should be at 1 turn out.
Drop the float bowls and see if there is any crud in there.
Put a filter between the carb and the pump.
Any crud in the filter on the pump?

 

[1NewBoatGuy]

Re: Engine Surging Question - 1985 85hp Force

Are all 3 cyl at 100#?
Check for water in the gas.
Pull the diaphram and check(even though it's new).
All the nuts tight?
Take some starting fluid and spray around the different area of the motor and at the base of the carbs(not in the carbs).
See if the motor picks up or slows when spraying.
The carbs should be at 1 turn out.
Drop the float bowls and see if there is any crud in there.
Put a filter between the carb and the pump.
Any crud in the filter on the pump?

Ill try the starting fluid trick tomorrow I don't have any and the stores are closed today, The gas is new so no water there. I did pull the diaphragm and it does look stretched. Is this normal? The diaphragm doesn't have much more than 10 hours on it. If that.
I took the carbs out and did drop the bowls, clean as a whistle actually. I blew air through the fuel port on the carbs with the floats down and they seem clear. The filter on the pump did look pretty good.
How much fuel pressure should I be seeing after the pump?
This definitely seems like a fuel problem but I really can't find any thing making itself obvious.

 

[1NewBoatGuy]

Re: Engine Surging Question - 1985 85hp Force

OK, narrowed this down to definitely the carbs being starved of fuel. The fuel pump seems to be pumping fine. All though the carbs fuel inlets seem to be too restricted to allow the fuel bowls to fill fast enough. Tomorrow I'm Gonna pull the carbs and check this out.
Would low compression give me poor vacuum?