Hitachi VC-42 Carburator

[Esteban]

....do you like spam just fried up or sautéed with a light sauce hollandaise?

while is

[bosque]

I seem to have a gap at the heat control valve shaft. I assume the open position of the HCV is counterclockwise?

Can't recall what direction it closes. Easy way will be to not the position when cold and then when hot. Also, when hot, it reaches a position from one it can't go any further, so try moving the valve in either direction to see where it will be normally when hot. At this position, the flow of exhaust gases tend to push the valve open. So even when the bi-metallic coil will move into one direction, if you give it power, the valve will give in to the pressure of the gases into its hot position.

Just a follow up visual......
Cold position:


Hot:

[Bigjoe]

69 Patrol, same 42-4a. I'm having a bit of trouble dialing it in. I've had the idle adjustment screw anywhere between 1/2 turn open to 3 turns.
and I can still get it to run solid but lean by adjusting the throttle adjustment screw. To get more fuel to the engine and not have it run so lean where should the idle screw be? And is it screwed out more air for the venture or more fuel? Manual says start a 2-3 turns. Just A bit puzzled and amazed it runs under all settings

[RiverPatrol]

I am not an expert on carbs, but I know the Hitachi has very little adjustment. If adjusting the throttle screw doesn't make any difference it sounds like the carb is worn and needs rebuilding.

[Esteban]

The slow-speed adjusting screw works only at slow rpms, when the throttle valve is almost closed. After that, it has no effect in the operation. In other words, at say 2000 rpms, no matter what the setup was, it won't affect the performance.

What I typically have done, after my timing is setup properly, is to adjust the rpms to around 500 with the throttle adjusting screw. Then I start turning in the slow-speed adjusting screw, until the engine starts to hesitate a bit. At this point I dial back about 1/2 to 3/4 of a turn, and call it good. You have to recheck the idle rpms again for fine tuning, and that's it.

I'm with RiverPatrol that you might need a rebuilding, or cleaning. Your slow air jet might be clogged. This carburetor is extremely smooth.

Take a look at the pictures in this topic: http://www.60patrol.com/forum/viewtopic.php?f=4&t=2560

On the right there's the VC-42 carb. The slow-speed adjusting screw is the one close to the bottom.

Good luck

[Bigjoe]

After playing with it a bit more. I would have to agree its time for a rebuild. There seems to be a lot of fuel entering around the side injector and or venture nozzle. I'm having a hard time finding information on the VC-42. and are there still kits available for rebuilds? Thanks Gang

[RiverPatrol]

The only rebuild kits might be in Oz. PM G60michael, he was able to locate a kit not too long ago. Maybe he can help you.

[ecigan]

Hi All—
I picked up a 1961 Model 60 earlier this year. Word was that it was restored in Bogota 2 years ago, then imported by way of Mississippi and… let’s leave it at that.
Anyway it came with the VC-42 carb fed by the original fuel pump. It had been running okay since I got it - definitely tuned very rich but running reliably nevertheless.
Last month I took it out of service to service the rear brakes, and by the time I got around to finishing that, 4 weeks went by without starting the engine.
When I tried starting it the other day, it flooded rather dramatically … to the point that there was fuel dripping out of it.
The gas cylinder was totally full, so my first thought was the float. I had been able to find a VC-42 rebuild kit so I replaced the float valve, but I had the same issue.
I then tried slightly bending the metal of the float hinge so the float valve would close with the float below horizontal — the Model P service manual recommends that —but still the same result.
My next thought was maybe I need a stiffer spring for the float valve … like maybe it’s getting hung up and not closing?
Also page 79 of the service manual notes with regard to the fuel pump, “In case spring pressure of diaphragm is tampered and made too strong, it will happen that gasoline overflows from the float chamber. Don’t monkey with the pressure of the rocker arm spring.” I haven’t done any monkeying with that spring but it makes me wonder about the time of the fuel pump in this.
Any & all advice appreciated! There are precious few Patrols in these parts, and the only one I saw here was a 1970 model so no VC-42.

—Eric
Framingham, MA

[RiverPatrol]

Welcome to 60Patrol! Congratulations on getting a Patrol.

It's hard to say what's going on with the carb really. The South American Patrols could have had any number of mysterious repairs done to them that can confuse the works. It sounds like there may have been an indication of something going wrong before if it was running rich, the VC-42 carbs don't usually have that problem. If you could take some pictures and post them perhaps that could help identify something amiss.

[Esteban]

Very strange behavior what you describe.

Don’t mess with the little spring inside the needle valve. I will verify that the valve is working properly first. Please check if the float doesn’t have a pinhole and is getting full of gasoline inside and not “floating”. An easy fix with a soldering gun.