tr4a Fuel Pump Problem

[riverstar]

Everything was working fine until I noticed that I had a leak coming from the diaphragm but fortunately I had a repair kit and fitted a new diaphragm, it was a bit of a fiddle as I had to enlarge the two slots at the bottom of the shaft to match the old one before I could get it to engage. Its all back together and not leaking however it is not pumping any fuel, there is a good flow from the tank into the glass bowl but nothing comes out at the carb end.

 

I would be grateful for any suggestions what may have gone wrong or what tests I should carry out.

 

Chris

[Don H.]

Does the priming lever pump fuel? The bowl should fill by gravity, so doesn't confirm much.

 

Possibilities: (not in any special order)

1. Diaphragm shaft not fully engaged.

2. One-way valves installed wrong

3. Cam lever positioned wrong side of cam as pump was inserted.

4. Block in line downstream from pump.

[peejay4A]

Have you perhaps fitted the pump with the operating lever on the underside of the camshaft eccentric?

 

Oops, just noticed Don's item 3.

Edited December 18, 2015 by peejay4A

[ianc]

Pressurise the fuel tank whilst a friend pumps the hand lever - this should force fuel into the pump and thereby prime it.

 

How to pressurise the tank? Get a plastic funnel which will sit in the fuel tank filler hole, insert a plastic tube into the funnel so that it jams at the bottom of the V, then blow down the tube.

 

Ian Cornish

[RogerH]

don't suck

 

Roger

[riverstar]

I am beginning to suspect the outlet valve is sticking but the upper body of the pump does not have a retaining plate the valves seem to be secured by a number of tabs once pressed into place, I tried easing one of the tabs back only for it to snap.

 

Can anyone offer advice on how I should go about in removing and re fitting then new valve (assuming the the valves I have will fit) without causing any damage

[Don H.]

Maybe send the pump to Dave Davies for his expert rebuilding & refinishing?

 

I just brought two pumps he did for me back in my luggage, including the original from my car where he replaced the cam lever. He's reasonably priced and does beautiful work. See multiple other threads for his contact info.

[Geko]

nope, edited

Edited December 19, 2015 by Geko

[riverstar]

I don't want to spend the time and money getting the pump refurbished when I have identified the problem and have the spare part sitting on my desk

[Don H.]

That's fine, riverstar -- these pumps are pretty simple. I misunderstood your concern about further damage to the valve housing.

[Lebro]

I would make sure that the valve is the problem before attempting to remove it - it could be a one way trip with that method of holding.

 

Bob.

[Mark1965TR4aBRG]

I'm now running a Pacet if you want to consider removing the original mechanical one..

[Steve R]

Just remove the tines, burred over bits, Is there a word for these?? and the valves will pull out, pop the new ones in and use a punch on the edge of the housing to secure it again, don't forget to get them the right way around.

Steve

 

PS Happy Christmas all

[Don H.]

Just remove the tines, burred over bits, Is there a word for these?? ...

 

It's called staking.

 

The earlier(?) pumps with the screwed-in valve clamp are a lot easier to service. Although I've replaced valves when I've rebuilt pumps, I'm quite sure every one I've taken out would have continued to work for a few more decades at least. It's a brutally simple, highly durable design. Are you sure the valves really need to come out, riverstar?

[riverstar]

Now fixed. I did need to replace one valve as it was sticking now working perfectly