Re: Excessive throttle pumping required to start
 

Mine started hard with the Weber also. I put a Holley 800 on it and it starts right up every time. It also picked up almost 2 mph. Much stronger throughout the rpm range. Gas mileage is just as good, too.

Re: Excessive throttle pumping required to start
 

[QUOTE=BajaBuddy]I thought you weren't supposed to use electric fuel pumps on a marine engine. QUOTE]

Many marine engines use electric fuel pumps. The mechanical pumps don't create enough pressure for EFI's.

They have been around for a long time. The pump in the bottom right of this picture came from a 1987 320 EFI, which I believe was Merc's first attempt at fuel injection.

Re: Excessive throttle pumping required to start
 

Glad it worked Offthefront.

Re: Excessive throttle pumping required to start
 

I have had several boats with the same problems that you have described. Set for a week then it takes all day to start. The problem was fixed by my mechanic very easily. My carbs were Quadrajets. He said that the fuel bowls leak down when they get older. He pulled the carbs off and sealed a small hole on the bottom of the bowl. (dont know details). When I got the boat back, WOW, just like new. Pump the throttles twice, and it fires up even after sitting for several weeks.

Re: Excessive throttle pumping required to start
 

Hydro, I will try also. Never heard that before. I pump mine 6-10 times when ice cold.
1993 502 Quad jets. It's not a big deal the way it is now but always looking for improvements. Tnks for your suggestion.

Re: Excessive throttle pumping required to start
 

I don't think I've ever seen a carb that had a bowl drain... I've seen leaky Holleys that drained... but I think what is happening is the fuel pump is allowing the fuel to drain back into the tank and the gas in the bowl is just evaporating. The last cars sold in this country that had carbs didn't have bowl vents that were open to the atmosphere.. they had to vent into a canister.. and that slowed down the evaporation rate. Fuel bowls on carbs are engineered to be as small as possible. In fact.. on quadrajet carbs there is a "spacer" made of plastic to displace some of the fuel. The reason for this is to maintain a more even level of fuel in the bowl at different angles. Boats of course don't have to start and run going uphill. If you were to look at a quadrajet,,, you will notice that it is a "centered" bowl.. the bowl is right in the center of the carb. If you look at a Weber dcnf... the bowl is in the front.. that way if the car is running up a steep hill.. the fuel is sloping toward the emulsion tubes and not away causing a lean condition. If you have ever driven an old Ferrari that had Webers... 275 GTB 6 carb version... 365 GTB.. or even the early carbed 308s... try backing up a steep hill.... every time you let the clutch out... the fuel runs away from the emulsion tubes and the engine stumbles... this was a common problem that was eliminated with fuel injection.

Re: Excessive throttle pumping required to start
 

I hear ya Reed but the bowls are empty in a couple days after standing in most applications and everybody has the same start up situation. Wierd eh?

Re: Excessive throttle pumping required to start
 

My electric pumps are secondary pumps the motors have a mechanical fuel pumps as a primary. The electric ones I use for priming.

Re: Excessive throttle pumping required to start
 

My Friend Bad Accelerator Pump In Carb Seen This Before .have Carb Rebuilt. I Have 30 Years Experience. And Make Sure The Choke Is Working.ps Trust Me!!

Re: Excessive throttle pumping required to start
 

Maybe so ....but sure as hell werks ....all these are bad Accel. pumps ?