3.0 omc carb setup, wont run right

[Nick Bain]

I went through the ignition, set up the carb to run and it surged a lot on the water. Topped of the gas with ethanol free 91 then took it out the next day and it idled out and died and I havent been able to start it since, trying any manner of carb adjustements. My main question is what the butterflys are supposed to look like at idle neutral. I have a service manual but its hard to understand where that should be, I guess the next thing to rule out would be compression and spark plugs, the choke works and its getting gas, but it seems like its flooded maybe as it smells like a lot of gas. IDK maybe its just plugs.

 

[Scott Danforth]

did you clean the carb. literally pull the carb apart, soak all the components and chase every passage with a fine wire to make sure they are clean?

 

[Nick Bain]

Yes I forgot to mention that I did that, I took it all the way down and found it clean cant remember If I did the wire thing but I did not see anything blocked. Also update compression good, plugs were black. carb likely out of adjustment as I had the butterflys slightly open and the the throttle linkage was set so the lever to squirt the gas in was like halfway engaged.

 

[Scott Danforth]

if plugs are black, its running rich or your ignition is out of adjustment

what did you set the points to? what was the dwell reading?

 

[Nick Bain]

I set it to the book for 91 octane with timimng light and points to .020. comp is a little high in the middle two and a little low in the end two 120, 140,150, 120. spec is 130. but only the #3 cylinder was spraying out a mist of gas when cranking which went away after I set the carb to book spec, I found it odd only #3 was spraying. ran out of time to check the spark again after cleaning the plugs with a dremel wire wheel. Looks, like Ill have to revisit the carb.

 

[Nick Bain]

Ok so while taking of the vacuum tube I see the hole is open through the manifold, is this right? It seems like it would reduce the vacuum to the manifold?

 

[Bondo]

Ok so while taking of the vacuum tube I see the hole is open through the manifold, is this right? It seems like it would reduce the vacuum to the manifold?

Ayuh,...... Isn't that the choke heat riser, 'n not vacuum,..??

Never seen vacuum tubes on a boat motor,.....

 

[hugh g]

Ayuh,...... Isn't that the choke heat riser, 'n not vacuum,..??

Never seen vacuum tubes on a boat motor,.....

Yep

 

[Scott Danforth]

I set it to the book for 91 octane with timimng light and points to .020. comp is a little high in the middle two and a little low in the end two 120, 140,150, 120. spec is 130. but only the #3 cylinder was spraying out a mist of gas when cranking which went away after I set the carb to book spec, I found it odd only #3 was spraying. ran out of time to check the spark again after cleaning the plugs with a dremel wire wheel. Looks, like Ill have to revisit the carb.

spec is 150 psi during cranking. the 120 is low, however it will run

what is your dwell? it should be 32. then what did you set the timing to?

if gas is running down #3, then your float is not set right. you literally may be pouring fuel down the intake.

by any chance is the clear tygon tube from the fuel pump to the spark arrestor full of fuel?

 

[Nick Bain]

would a bad manifold make it not start or run right? it doesnt spit water or seem to have exhaust problems

 

[Nick Bain]

not sure the choke is set right the manual says the start circuit it should be fully closed. but when i start it, it flutters open

 

[Nick Bain]

spec is 150 psi during cranking. the 120 is low, however it will run

what is your dwell? it should be 32. then what did you set the timing to?

if gas is running down #3, then your float is not set right. you literally may be pouring fuel down the intake.

by any chance is the clear tygon tube from the fuel pump to the spark arrestor full of fuel?

no it is not, but me and a buddy got it running to idle at WOT with lots of black smoke and really advance timing, then I saw fuel dripping down the venturis after it was shut off, so somehting must be amiss with the carb.

 

[Scott Danforth]

welsh plugs are leaking or your needle/seat or float are needing attention