SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: torvald68 on August 04, 2011, 09:56:54 AM

Title: Starting over.
Post by: torvald68 on August 04, 2011, 09:56:54 AM

Ok everybody I decided to start back to square one with my 850 double pumper. My boat is a 1978 Nordic pickle fork with a mostly stock 454 with a small b&m blower. I am running a summit 130gph electric fuel pump. Bassett headers. Berkeley pump. Where should I start on the jetting of the carburetor? What size accelerator pumps? Initial timing? Hopefully a couple of you guys with blower motors can help me establish a baseline. Thanks for your help and time.

Title: Re: Starting over.
Post by: Brendella Pickle on August 04, 2011, 11:45:49 AM

Input... need more input.

Actual displacement, compression ratio, cam, Heads, Boost, etc

Title: Re: Starting over.
Post by: torvald68 on August 04, 2011, 08:43:36 PM

454 stock bore, 8.5:1 compression, stock cam and  oval heads, 850 double pumper. Motor is stock and the blower is a B&M 177. The instructions claim 5 to 7 psi of boost. What it is doing is backfiring and shutting off when you crack open the secondaries. So cruising around it is fine. But when you really get on it  it starts moving good and then backfires and shuts off. Any useful information would be greatly appreciated.

Title: Re: Starting over.
Post by: metallicats33 on August 04, 2011, 09:30:07 PM

Came across this a while back, it might help you out:

http://www.fortunecity.com/silverstone/pontiac/101/sctech.html (http://www.fortunecity.com/silverstone/pontiac/101/sctech.html)

Title: Re: Starting over.
Post by: HDriderTH on August 05, 2011, 06:56:16 AM

make sure your acc pump is working on the secondaries. Go up about 4 jet sizes if not

Title: Re: Starting over.
Post by: torvald68 on August 07, 2011, 06:07:11 PM

Thanks for the leads in the right direction. That link is very helpful. And the advice on fattening up the secondaries is also in line with the link.