Carb help
Apr 15, 2020 11:43:44 #
Get some blue carb additive for ethanol removal
Use no gas with ethonal In it
It will clog your engine up
Had same problem with my in board motor
Check fuel filter also
Could cause problem
Use no gas with ethonal In it
It will clog your engine up
Had same problem with my in board motor
Check fuel filter also
Could cause problem
Apr 15, 2020 12:19:55 #
fishrmans
Loc: Waushara Cnty Wisconsin and Port Charlotte Fl
When you get done checking everything else, like I did, check the anti siphon check valve in the fuel tank. I have had two boats with that problem. One was a Bayliner but that really makes no difference. The valve can get gummed up and will not let enough fuel through. It has a little ball with a spring that doesn’t open enough to let fuel through in the proper amount. A cheap fix for around 12-15 $. I spent around 150$ the first time until I found this. The second boat this was the first thing I checked.
Apr 15, 2020 13:42:17 #
E.pa.al
Loc: Martin's Creek
I believe that carb is rated for about 600 hp, double check fuel flow or possibly a check valve
Apr 15, 2020 16:02:16 #
jerseyguy
Loc: Ocean County NJ
Rocky from CA wrote:
Back to the 78 Bayliner Victoria I spoke of earlier. The engine bogs down at about half to 3/4 throttle. It picks back up when wide open but I still am missing speed. Should I rebuild my carb or buy a rebuilt on line? Several people have told me to steer clear of online rebuilt carbs. It is a Rochester quadrajet. 350 Volvo Penta engine. What are decent prices for either way I go. This is all so new to me.
Ive been known to sometimes be wrong, but.........
Sounds like a bad accelerator pump in the carb. It's a simple diaphragm that gives a shot of fuel so the engine doesnt stumble when you give it extra throttle.
Rebuilding the carb isnt really that hard. Buy a rebuild kit. You could always buy a rebuilt if your rebuild doesnt go well.
Accelerator pump! Look into throat of carb and see if you get a strong shot of fuel as you goose the throttle. If not-accelerator pump. Rebuild.
Apr 15, 2020 16:43:03 #
Rwest
Loc: Oceanside, Ca
Hello Rocky,
Like anything, you get what you pay for so if it’s cheap, it’s probably cheap. But there are some good rebuilds out there.
It does sound like a fuel issue. Does it hesitate during acceleration or just bog down while trying to maintain a speed at half to 3/4 throttle?
If your mechanically inclined, this isn’t a hard rebuild to do yourself. Most important adjustment is the float level.
Sorry for all the questions, I was a ASE Master Certified technician.
Like anything, you get what you pay for so if it’s cheap, it’s probably cheap. But there are some good rebuilds out there.
It does sound like a fuel issue. Does it hesitate during acceleration or just bog down while trying to maintain a speed at half to 3/4 throttle?
If your mechanically inclined, this isn’t a hard rebuild to do yourself. Most important adjustment is the float level.
Sorry for all the questions, I was a ASE Master Certified technician.
Apr 15, 2020 16:43:48 #
Apr 15, 2020 17:28:48 #
The Quadrajet was always notorious for bogging. The reason is those HUGE secondary venturis the carb has. It sounds like yours are opening too quickly.
From the way you described it, running fine at slow speed and wide open tells me that the jets aren't clogged. If you ease the throttle and it still runs good this tells me that the midrange needles aren't stuck.
You can buy a spring kit that has about five different springs in it. They go in a dashpot on the side of the carb and they limit how fast it opens. Simply put the "fastest" spring in and try it. If it bogs go to the next slowest spring. Continue changing the spring until it accelerates cleanly.
The diaphragm in the dashpot may have gone bad. If it's that old (78 I think you said) the diaphragm may have become brittle and cracked resulting in the secondaries opening way too quickly. Summit may have a dashpot and the spring kit.
From the way you described it, running fine at slow speed and wide open tells me that the jets aren't clogged. If you ease the throttle and it still runs good this tells me that the midrange needles aren't stuck.
You can buy a spring kit that has about five different springs in it. They go in a dashpot on the side of the carb and they limit how fast it opens. Simply put the "fastest" spring in and try it. If it bogs go to the next slowest spring. Continue changing the spring until it accelerates cleanly.
The diaphragm in the dashpot may have gone bad. If it's that old (78 I think you said) the diaphragm may have become brittle and cracked resulting in the secondaries opening way too quickly. Summit may have a dashpot and the spring kit.
Apr 15, 2020 17:54:05 #
Rocky from CA wrote:
Back to the 78 Bayliner Victoria I spoke of earlier. The engine bogs down at about half to 3/4 throttle. It picks back up when wide open but I still am missing speed. Should I rebuild my carb or buy a rebuilt on line? Several people have told me to steer clear of online rebuilt carbs. It is a Rochester quadrajet. 350 Volvo Penta engine. What are decent prices for either way I go. This is all so new to me.
Ted’s carburetor in Lancaster Ca only does Quadrajets the best in the US and doesn’t charge a lot he did mine and it was better than new
Apr 15, 2020 17:57:52 #
Rocky from CA
Loc: Central California. Home base is Bakersfield
Bogs down during acceleration. Always at the same speed. And not to many questions. I appreciate everyone's help
Apr 15, 2020 17:58:34 #
Apr 15, 2020 17:59:50 #
Rocky from CA
Loc: Central California. Home base is Bakersfield
Thanks for the info. It bogs down and then picks back up after throttling past the area where it bogged down.
Apr 15, 2020 18:10:15 #
Rwest
Loc: Oceanside, Ca
I think Jerseyguy was right. Accelerator pump. Have it rebuilt and it should run fine. I hope they check the float. I’ve had a lot of absorb gasoline and sink a little causing the fuel level to drop in the float bowl making it harder to draw fuel into the intake.
Good luck. Let us know how it turns out.
Good luck. Let us know how it turns out.
Apr 15, 2020 18:20:17 #
Rocky from CA
Loc: Central California. Home base is Bakersfield
Will do. Thanks again for all the input
Apr 15, 2020 18:34:57 #
Apr 15, 2020 18:37:03 #
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