Where in the carb should I spray the fogging oil and how much?

[babikov]

Hi,

Where in the carburetor should I spray fogging oil? I lifted the flame arrestor but there are quite a few holes underneath.

My engine is 1993 4.3LX/V6 Alpha One Thunderbolt Ignition, serial number OF0244564. The carburetor looks like Weber 4 barrel. In the front part of it there is a plate (choke plate? not sure?) with two round holes below it; in the rear part of the carburator I see two round holes (air valves? not sure?). So where should I spray?

And the second question is: how much of the fogging oil?

Thanks for your help.

 

[ErieRon]

Re: Where in the carb should I spray the fogging oil and how much?

Here's a link to a step by step from Don S. on winterizing your engine (item 13);

http://forums.iboats.com/showthread.php?t=178695

Here's a link to where you can download your factory service manual for free;

http://www.4shared.com/file/121507388/2e92adf3/MercruiserManual7.html

Basically, you are going to spray the fogging oil into the carb via the throats under the choke plate. The idea is to start slowly so it can fully circulate and then stall the engine by spraying it more rapidly. There should be instructions on the can as well.

Hope this helps.

 

[babikov]

Re: Where in the carb should I spray the fogging oil and how much?

ErieRon,

Thank you. I saw the instructions by Don, and I have read the mannual (actually, I think my manual is number 18, but I downloaded both, they say the same thing about winterization).

I understand general procedure, but my question was where to spray. The manual says to spay into "carburator bores", but I see four of them in the carburator.

So, you are saying to spray into the throats under the choke plate, which is a large plate (almost rectangular, two corners are rouded) in the front part of the carburator.

I am asking because I see there two more round valves, with two more throats under them, and you are saying I should not spray into those? Right?

Thank you.

 

[Chris1956]

Re: Where in the carb should I spray the fogging oil and how much?

On that 4 barrel carb, two of the barrels have choke plate. Those are the primaries, and are the ones that operate at idle, which is the speed at which you will be fogging the motor. The secondaries will be closed at idle.

 

[Bt Doctur]

Re: Where in the carb should I spray the fogging oil and how much?

Keep spraying it in untill the motor stalls or it begins to smoke heavily

 

[babikov]

Re: Where in the carb should I spray the fogging oil and how much?

Chris,

Thanks! Now I see the point!

Do you guys spray through a little pipe (sold with the fogging oil) or directly from the spray can?

 

[ErieRon]

Re: Where in the carb should I spray the fogging oil and how much?

Sorry, I should have been more clear. The other poster explained it well. The larger choke plate will open at idle as your engine warms and stay open. The secondary air valve plate will only open at higher throttle/demand.

I don't use the tube, but it probably doesn't matter. You'll see when you do it...it will suck the oil mist right in to where it needs to go. It's just drawn in with the air that it needs for combustion.

Start slow and let the engine draw it in. You'll hear the engine struggle a bit and kind of choke, then slowly increase your oil until the engine stalls. It's a quick process because the mixture goes directly to the cylinders. I never timed it, but it's probably a 15-20 second process.

 

[chuck in WA]

Re: Where in the carb should I spray the fogging oil and how much?

FWIW, I have to use 2 cans at once to stall my engine (3.0). If you haven't already been to the store, consider buying 2 cans when you go.