Standard jetting for quadrajet 4bbl on a 5.0 mercruiser

[Ausycol]

G'day guys, great site...however I'm new & learning how to drive it.

I recently purchased a Chris Craft with a quadrajet 4bbl (17059288) on a mercruiser 5.0. The motor has had the points ignition replaced with electronic ignition otherwise it's a stock setup.

Its a little sluggish taking off & will stall at idle when warmed up after a run. I've ordered a rebuild kit which I'll be freshening it up with through the week and having pulled it down it was certainly in need of a clean. Research tells me the carb was originally fitted to a 350 or bigger motor & I'm concerned about the jetting.

My question is around the jetting and I'm having trouble finding the correct jetting for the 305ci motor.

The current numbers are;

Primary rods - 41
Primary Jets - 68

Secondary Rods - DDE (with another E underneath).

Can anyone please advise what I should be running?

[Cliff Ruggles]

That jet/rod combination is fine in a stock 305 Marine engine and it would have nothing to do with stalling at idle or sluggish/stumbling right off idle, etc.

The idle and off idle fuel delivery in a Marine carburetors is fairly generous as they are not emission calibrated so I'd look there for a cure to your issues.

Also check the distributor to make sure the mechanical advance is adding timing as engine rpms increase, especially right off idle.  Often the mechanism is rusted or grease dried up and lacking spark advance will also cause off idle issues same as the carb not delivering enough fuel.

Hopefully you put one of our kits in it, and I'll mention here as I have many times that most if not all of the Marine kits we're seeing over the counter or available on line will NOT have the correct parts in them, or good quality parts, both of which lead to less than desirable results on the finished product.......Cliff

[Ausycol]

Thanks for your response Cliff it's greatly appreciated,

Having gone through the charts of Jets, primary & secondary rods I had a feeling I was somewhere in the ball park so your confirmation has helped a lot.

I'll be re-kitting the carb this week & hopefully testing next weekend so I'll repost and see how it goes.

The fact you took the time to answer me and provide the detail you did I hope I can link you into Aus & all of us guys that can benefit from your help.

Kind Regards.

Col...

[Cliff Ruggles]

Keep in mind what I've been saying about rebuild kits.  No kit available is as complete as ours nor will any of them have the correct Marine components in them.  Doesn't matter what the source is everything we see in here has the wrong N/S assembly and accl pump in them, and no other kits will have the secondary cam/spring nor the retainer for the power piston to keep it down during assembly.

I push parts really hard, no big secret there because we have to make money to stay in business, but even more important is that we want our customers to get the best end results and dead solid reliable in long term service.

Near 100 percent of the freshly "rebuilt" carburetors that end up here because the owner or nobody else can get them to work correctly will have the wrong parts and/or low quality parts in them. 

We stepped up to have better parts made for that reason, and why we offer lifetime replacement on our accl pumps and to date have never had to replace one, they are that good......Cliff