throttle plate setting at idle ( solex Carbs)

Can anyone tell me if the throttle plates should be closed at idle ( 900 rpm) on twin solex carburators for a Volvo 250 engine ? I think the idle jets are feeding fuel above the plates and for fuel to flow the plates should be slightly open to get to 900 rpm but I may be wrong!

Re: throttle plate setting at idle ( solex Carbs)

On the 44PA1 carbs, yes, the idle speed adjust screw does adjust the throttle plates. Yours are a little different but the linkage operation is pretty close to the same.

If I recall correctly, that carburetor has a spacer plate with two gaskets at the base. Based on your other posts, I'm wondering if you have the base plate oriented correctly. Just throwing that out there as an idea, not sure if that's the problem or not.

Re: throttle plate setting at idle ( solex Carbs)

Thanks Pirate. So , in other words if the throttle plates are completely closed the engine will not start because fuel will not flow! appreciate your idea on the gasket orientation bot there has been no carburetor disassembly prior to this problem. However, the carbs were removed and completely blown out and cleaned with carb cleaner. Upon reassembly problem persists ( no fuel flow). The weird part about it is that the engine can be started by dumping gas or ether into the carbs but only temporarily without opening the throttle and thus the throttle plates . However if you stick your fingers down the venturis fuel will flow with the plates closed! I can't engage the throttle without the boat being in gear so this won't work at the dock when trying to idle out of gear.
I am going to try adjusting the idle speed until I see the plates slightly opened. This should create enough delta p for fuel flow!
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Re: throttle plate setting at idle ( solex Carbs)

Based on what you've said,I'd be inclined to disconnect the throttle cable so that I could rev up the engine and not worry about it being in gear.

Once you're able to keep the engine running, you should be able to adjust the idle mixture screws. It sounds like the idle mixture is the main culprit. Again, you'll need to consult the manual for your carbs. I believe they recommend starting with those jets quite a few turns out. More so than most of us would consider normal.

Also need to ask when the problem started. Is this something that happened all of a sudden and was the boat running fine before?

Edit - Just wanted to mention that we discussed the idle mixture in a previous post. My assumption right now is that the mixture is too rich. Turning the mixture screws in from the recommended starting point should make it leaner.

Re: throttle plate setting at idle ( solex Carbs)

Pirate,
Thankyou for all the help. I don't really know if I corrected the problem by blowing out the very small vent holes for the idle jets or by adding CRC gas treatment to the fuel tank. Initially blowing out the vent holes didn't make a difference but I did note that good carb cleaner flow was not instantaneous on one of them! I think I might have missed those vents when I cleaned the carbs on the bench. I was about to give up but found some gas additive in my tool box and decided to add about 3 ounces to my tank. After that I decided to try starting it one more time and it fired up and is running like a swiss watch!
Idle mixture was not the issue at all. Of course I had to adjust the idle speed once I had it running as I had been playing with the linkage and settings while trying to keep it running . I did discover after the vent cleaning that I could keep it running ( minimally) without keeping my fingers in one of the carbs. This gave me a free hand to mess with the idle screws. When it finally ran on it's own the idle was about 2500 rpm to high. I trimmed it down to 900 and it purrs like a kitten!
My bet is a plugged vent and not the fuel additive but I am not about to put money on it!
Thanks again for taking the time to respond to my problem.