1959 Rapier Carburetor Idle

[husky drvr]

The accelerator pump (power valve)

The accelerator pump is not the power valve(PV). The WIP* carb pairs did not have the parts for the PV installed but did have the needed ports and passages to allow any carb body to be built at the factory to WIA* specs (with the PV).

A definition of PV from a search:

A carburetor power valve is a vacuum-operated fuel enrichment system that provides additional fuel to the engine under heavy load or high power demands. It's essentially a valve that opens when the engine vacuum drops below a certain point, allowing more fuel to flow into the main well of the carburetor. This extra fuel helps the engine maintain a proper air-fuel ratio and power output during acceleration or when the engine is under stress
The service manual calls it the "bypass valve" instead of PV.

Hope this helps,

 

[Chrisp Rapier]

The accelerator pump is not the power valve(PV). The WIP* carb pairs did not have the parts for the PV installed but did have the needed ports and passages to allow any carb body to be built at the factory to WIA* specs (with the PV).

A definition of PV from a search:

A carburetor power valve is a vacuum-operated fuel enrichment system that provides additional fuel to the engine under heavy load or high power demands. It's essentially a valve that opens when the engine vacuum drops below a certain point, allowing more fuel to flow into the main well of the carburetor. This extra fuel helps the engine maintain a proper air-fuel ratio and power output during acceleration or when the engine is under stress
The service manual calls it the "bypass valve" instead of PV.

Hope this helps,

View attachment 35519

Oh, thank you for that. I was unaware. So I just want to make sure the passage is not blocked?

 

[husky drvr]

So I just want to make sure the passage is not blocked?

Your WIP* carbs don't use the passage because they aren't fitted with the PV parts. However, if the top cover gasket has been damaged, the passage could become a vacuum leak to the manifold. The WIP* carbs seal and don't use the passage. Because the passage travels throttle plate base to top cover, any joint along that passage could leak directly to the manifold.

Hope this helps,

 

[Chrisp Rapier]

Your WIP* carbs don't use the passage because they aren't fitted with the PV parts. However, if the top cover gasket has been damaged, the passage could become a vacuum leak to the manifold. The WIP* carbs seal and don't use the passage. Because the passage travels throttle plate base to top cover, any joint along that passage could leak directly to the manifold.

Hope this helps,

Ok I understand. Yes that is helpful. I will examine it, thanks.

 

[Chrisp Rapier]

Pretty weird. If I were you would switch back to the previous seating and check whether the iseue is fixed. Can't realy believe you created an air leak unless the top seal got damaged...

I took a honning stone to the carb body top surface. It had a couple of high spots that I took down. One was particularly bad at one of the central bolt holes. They could very well be the cause of my problem. I also put a very thin smear of fuel resistant gasket dressing on the gasket, both sides. I think it fixed the problem. I am able to once again close the adjustment screw to bog the engine, so I seem to have stopped a vacuum leak.

 

[bernd_st]

Sounds as if you cured the culprit. Very good. Needless to stress the Zenith top seal and the surfaces need to be clean and true...

 

[Chrisp Rapier]

Sounds as if you cured the culprit. Very good. Needless to stress the Zenith top seal and the surfaces need to be clean and true...

Haha. Well it did sound like I cured the culprit. Perhaps I did cure one or two of them but then after running fine for a day it suddenly stalled out on a slow down around a turn. It then ran terribly again. It is the front carburetor again. I am very sure dirt is getting in from the tank. I will open up the carb and I am sure it will be dirty and I am sure the idle jets will be clogged. It all happened so soon after replacing the temporary filter I had under the car. My thoughts are that the garbage was still in the line forward of my added on filter. I did not clean out the glass collector with the strainer. I am sure it must also be dirty. What does one do when opening the glass when it is full of fuel? Do I put a bunch of rags around it and open it? Does the strainer actually do anything?

 

[bernd_st]

Think we talked about the neccesity to clean up everything related to the fuel supply already, otherwise you'll run in repeating issues.
Yep, a bunch of rags under the pump body will soak up the remaining fuel. You may opt to disconnect/close the incoming fuel line and empty the glass bowl as much as possible with a few strokes on the manual pump lever. This will reduce the amount of fuel getting wasted...

 

[Chrisp Rapier]

Think we talked about the neccesity to clean up everything related to the fuel supply already, otherwise you'll run in repeating issues.
Yep, a bunch of rags under the pump body will soak up the remaining fuel. You may opt to disconnect/close the incoming fuel line and empty the glass bowl as much as possible with a few strokes on the manual pump lever. This will reduce the amount of fuel getting wasted...

You seem to be correct about everything and yet I forge ahead without doing what you suggest, so here I go again. I am going to clean out the fuel pump stainer reservoir and my carbs and hope the tank is running out of contaminates and that the new filter catches the rest. Maybe I will just open the access hatch in the trunk and have a look in the tank.

 

[Asm109]

The tanks in my Tiger were shedding a black tank lining. Waiting for all of that to shed and be caught in a filter is a fools errand.
Pull tank, hot tank it and re install or put in a tank creme.

 

[Chrisp Rapier]

The tanks in my Tiger were shedding a black tank lining. Waiting for all of that to shed and be caught in a filter is a fools errand.
Pull tank, hot tank it and re install or put in a tank creme.

I had my tank out and cleaned it pretty well. There was no black tank lining in it. It was actually fairly clean plain steel on the inside. There was some tar like deposits in spots which I cleaned up. The opposite sides of the baffles was difficult for me to see and reach however.

 

[bernd_st]

If the tank has been cleaned I really wonder where the residue is coming from. Can be only remains in the line or in the pump chamber. Did you blow through the lines with compressed air ?

 

[Chrisp Rapier]

If the tank has been cleaned I really wonder where the residue is coming from. Can be only remains in the line or in the pump chamber. Did you blow through the lines with compressed air ?

The tank cleaning I did two years ago. The cleaning was with brushes and gasoline to remove the tar like deposits. I also used gasoline and nuts and shook the tank and rattled it over and over till the gas came out clean. That said I could not see what was going on behind the baffles. The fuel line I completely replaced from the tank to the pump.the pump I rebuilt. I drove the car around for a year now sparingly. Maybe once a week for a couple of miles. I was going through a year of carburetor woes. I think I have most of that sorted for now. The rear carb does not seem to get the debris in the bowl. Probably the front one is the straighter and shorter route for the gas to flow to. I am guessing that debris collected in the pump strainer which I did not yet clean out since the new dirty fuel issue.

 

[Paul354]

I cleaned my fuel pump about 4 years ago there's a trough inside the glass bowl rubber seal this is what I cleaned out from there
It looks like pebbles but when I crushed it between my fingers it was a fine powder dirt and bits of the fuel tank linner

 

[Chrisp Rapier]

I cleaned my fuel pump about 4 years ago there's a trough inside the glass bowl rubber seal this is what I cleaned out from there
It looks like pebbles but when I crushed it between my fingers it was a fine powder dirt and bits of the fuel tank linner

View attachment 35639

Wow, that is a mess. Now I am curious what resides in mine. When I clean it this weekend I will photo it if it is junkie.

 

[Chrisp Rapier]

I cleaned my fuel pump about 4 years ago there's a trough inside the glass bowl rubber seal this is what I cleaned out from there
It looks like pebbles but when I crushed it between my fingers it was a fine powder dirt and bits of the fuel tank linner

View attachment 35639

Ok, so this weekend I cleaned the the bowl and the jet of the front carburetor. There was a little debris in it. Small sediment. I also cleaned the fuel pump strainer collector. It had a little bit of fine sediment. Just a little. I then opened the tank access on the trunk and shined a flashlight down and had a look. Yes there is some dark fine sediment on the bottom. It's not bad. Of course the fuel draws from the lowest part of the tank so it all will find its way eventually down the line. The filter I had under the car did a good job of catching most of it. I will just keep replacing the filter more frequently and see how it goes. The car is running the best it has so far. I have the idle down to about 750 now. I'm happy today and fingers crossed about the bit of sediment left in the tank.

 

[bernd_st]

Good so far. If I were you I'ld consider to clean the tank thoroughly again. Sediment in there is never good news...

 

[Chrisp Rapier]

Good so far. If I were you I'ld consider to clean the tank thoroughly again. Sediment in there is never good news...

I am sure you will prove to be correct again, but I will put off the tank cleaning for a bit. My tank is full right now. Perhaps I will run the tank down as much as possible and see if I can siphon off the sediments and clean the tank while still in the car.

 

[bernd_st]

Should be ok. Hope your fuel filter is good enough to prevent sediments entering into the pump or even the carb float chambers...

 

[Chrisp Rapier]

Should be ok. Hope your fuel filter is good rnough to prevent sediments entering into the pump or even the carb float chambers...

Well not ok. See I decided to drive it to work, 10 mins. From my house. I arrived successfully at work. Good. Then departed successfully from work. Good. However I did not arrive home successfully. I lost power and stalled half a mile from home. It felt like running out of gas however the pump reservoir was full. I checked the carbs. Rear accelerator pump was working but the front not. I had tools in the trunk. Excuses me...boot. I then opened up the carb. The bowl was empty. I figured if I could get gas in the bowl, I might be able to make it home. There was a gas station two doors down. On the way was a discarded Gatorade bottle, which I rinsed out at the gas station. I pumped gas and used it to fill the bowl. Car started and I made it all the way home.
There must be garbage accumulated in the short section of fuel line to the front carb. Maybe collected under the float needle seat. It wasn't the float and needle. It was in the open position. Whatever obstruction it was cleared because I do not think I would have made it home on what was in the bowl alone. I even had the car idleing in the drive a while.