Mercruiser won't idle
 

Hi engine experts,

I recently changed intake manifolds and rebuilt carbs on my twin Mercruiser magnum 350's. These are the later ones with vortec heads. Now one engine won't idle. If I pump the throttle a couple of times it'll fire and then die again in a second or so.

I cleaned out the carb but this didn't help - and I've since swapped carbs with the other running motor and no difference. I've also swapped ignition modules and again no change.

My synopsis is there must be a significant vacuum leak in the intake manifold to head seal - I re-used the old gasket which was a paper style, rather than the rubber insert vortec type.

I'm now going to change the intake gaskets to the rubber insert vortec style (felpro version) but just wonder if there's anything else I should consider? I'm confident I have the timing right, and the way the engine fires after pumping the throttle indicates this to me also.

Appreciate any advice.

Cheers,

Craig
( Scarab 34 )

keep the paper type...the rubber on metal ones are junk..felpro makes the good thick paper ones