V.p 3.0 shakes bad at low rpm's

[maizam]

First of all thanks to all that helped me with the timing issue.

Same boat and motor 3.o v.p . The timing has been set. The engine wont smooth out below 1000 rpm's in neutral. If i try to drop the rpm's it goes into major shakes and it rattles the entire boat i set the mixture screws to 1 1/2 turns out from closed????? When i give it gas above 1300rpm it smoothes out and it seems ok but in neutral or in gear idle speed it goes into convulsions. Hheellpp.

 

[Bondo]

Re: V.p 3.0 shakes bad at low rpm's

Ayuh,... My guess is the low-speed circuit/ idle circuit of the carb is boogered up....
That screw might hold the key, the 1, 1/2 turns is merely the starting point of tuning...
Or, it could just be Crap in the carb...

 

[Don S]

Re: V.p 3.0 shakes bad at low rpm's

i set the mixture screws to 1 1/2 turns out from closed?????

Those are only PRELIMINARY adjustments. Once you get the engine running and warmed up and the choke open, then you fine tune the adjustment, and those Holley carbs are really picky about mixture adjustments.

 

[maizam]

Re: V.p 3.0 shakes bad at low rpm's

Oh no. Water in oil. Pulled the head and #4 cylinder is clean,shiny and wet. I"m hoping its just the head gasket. How can i be sure. The engine ran good except for the shaky ideling all day.

 

[oops!]

Re: V.p 3.0 shakes bad at low rpm's

examine the head gasket. and pressure test the mainifold.
usual reasons for water in the oil is a cracked block or head that cannot be repaired.
it is possibly the head gasket. and only replacing will tell.

 

[maizam]

Re: V.p 3.0 shakes bad at low rpm's

Will do. Should the head bolts be replaced or are the old ones ok to reuse? boating boating i just can't win.

 

[oops!]

Re: V.p 3.0 shakes bad at low rpm's

unless they are stripped......they will be fine.

 

[maizam]

Re: V.p 3.0 shakes bad at low rpm's

Would overheating cause the headgasket to blow and mix oil. The oil has small amount of water intruding into it as it is just becoming milky. the #4 piston is all clean vs the other 3.

 

[Angrywasp]

Re: V.p 3.0 shakes bad at low rpm's

Yes overheating will definitely cause the headgasket to blow. The #4 cylinder being clean indicates it had a leak into that cylinder for a while basically steam cleaning the piston. There may be other issues though like others have said.