1975 mercruiser 140 i/o carb prob

[patrick882]

Re: 1975 mercruiser 140 i/o carb prob

think i might have figured it out my carb kit came with three different venturi cluster gaskets and i think i put the wrong one on will have to wait till tomorrow to fix dark now im sure thats the problem can i buy one of those resistors for the wire from the battery to the coil

 

[ziggy]

Re: 1975 mercruiser 140 i/o carb prob

glad ya think ya found the problem man.... hope so...

no i dont have a service manual they do no good for me have had haynes manuals and things dont have much use for them

cause if ya believe that statement, ya ain't never gonna have a hope, how are ya even gonna know what the specs for yer engine are w/o one, let alone proper proceedures for repair...... ya need mercruiser service manual #2, C-90-71707. assuming you have a 75 mercruiser 140, it'll have the facts in it for ya....

 

[Flukinicehole]

Re: 1975 mercruiser 140 i/o carb prob

Where do you live? Does your gas have ethanol there? If so with your bog I would have checked my gas first. Here in the NE we get a lot of phase seperation and it does what you describe. You have to check your gas and water seperator if you have one. You might have rebuilt and rerebuilt the carb for no reason. Get a clymers manual.

 

[fishrdan]

Re: 1975 mercruiser 140 i/o carb prob

no i dont have a service manual they do no good for me have had haynes manuals and things dont have much use for them and where am i supposed to look for this spark

IMHO, Hayes manuals are a waste of paper and ink, I have a few of them and they only contain the information you already know

Go buy a Seloc or Clymers manual for your engine, there is soooo much info in them it can be overwhelming at times, good stuff!

If I understand your problem correctly:

-Before the carb was rebuilt the engine was cutting out at bogging at 1/2 throttle,,, starved for fuel?

-After the carb was rebuilt it will not start,,, starved for fuel?

I had a similar situation, turned out the fuel line had a split where it connected to the fuel tank. No fuel was leaking, but the split hose caused the fuel pump to suck air, took for ever to prime the carb and starved the engine for fuel at top end. Even caused the boat to die at one point and I couldn't get it started again,,, until I cut out the split section.

 

[Don S]

Re: 1975 mercruiser 140 i/o carb prob

Seloc and Clymers are also a waste of money, a little bit of info on a lot of engines. Then the information they have may or may not be correct.
Get the OEM manual.

 

[patrick882]

Re: 1975 mercruiser 140 i/o carb prob

just curious here.... on the gas tank i bought it has a vent screw in the top of the lid should that be open to vent or closed to create vacuum

 

[starsnstripers]

Re: 1975 mercruiser 140 i/o carb prob

What kind of tank? is it an outboard tank? The tank for you engine needs to be vented for fuel to empty out of the tank i do believe. Patrick check your private messages too. The vent should be open, but i'm not sure what kind of setup it is hopefully the vent isn't inside the boat. Inboad outboards normally have an exterior vent. If your tank is totally closed off it might be causing the fuel to be restricted from flowing to the carb.