I need some help please

[tommy8604]

I've got a 94 Crownline with 5.7 bored .030 with thunderbolt IV. Last year I had to replace the cam and had one given to me. The attached photo is the cam I installed. I've had the quadrajet carb rebuilt but I can not get this thing to idle below 1000 rpm. I've checked the power piston and it's staying closed. I've messed with the mixture screws and I have no adjustment with them. only thing I have not done is drill out idle ports. Just wanted more opinions before I did that. Now anything over 1000 rpm and it runs like a champ. I'm not sure about the cam I put it so ANY info about it is greatly appreciated.Ive also tried to time with vacuum and it did best at like 20 something BTDC. Didn't think that was right. Has a new cap, rotor, plugs, wires, fuel filter, antisiphon valve and fresh gas. I only run 91 ethanol free.

 

[Bt Doctur]

intake gasket leak, carb base gasket, throttle cable

 

[Rick Stephens]

Looks like a reasonable cam for a boat motor, not that I am the big expert on cams, but the numbers are basic stock RV kind of numbers.

What kind of compression does the motor have?

When you had a vacuum gauge on it, was the needle steady at idle?

Have you double checked firing order? (hear that one over and over again)

I would be very hard pressed before I'd go drilling out idle circuits......

 

[tommy8604]

when the idle is steady the needle is steady. I'm wondering about a gasket leak. I wanted to test that today but ran off and forgot something to spray. I have checked firing order but not compression. I talked to a guy today that knows cams and he told me that cam wanted more timing.He is also leaning towards a vacuum leak

 

[alldodge]

I'm finding it has an rpm range from 2000 - 5600 so its not good for marine use, need to get the low end down in the 1600 area

 

[Bondo]

Ayuh,.... I think that cam is Huge for a boat motor,....