You are going to need a fuel pressure gauge suitable for a carburettor system. Do not use a fuel injection pressure gauge because their accuracy at carb system pressures is poor. Measured at the outlet of the pump the pressure should be 1.5 - 3.5 psi according to the Volvo service manual. You will need a Tee fitting in the line to do the test. If the pressure is above 3.5 psi the pump is the problem. If the pressure is below; but, close to 3.5 psi it is probably still a problem.

There is a spacer between the pump and the block. There are different thickness spacers and you need to make sure that you have the correct spacer as that changes the position of the arm relative to the operating cam which alters the pump stroke. That said, even with the correct spacer others have reported problems with excessive fuel pressure. It seems like there might be a batch of incorrectly designed pumps floating around.

Measure the pressure. If it is above 3.5 psi and the spacer is correct you need to have a discussion with CVR about them fixing the problem. If the pressure is less than 3.5 psi, then I would look at your float needles. Specifically, when messing around with the piping did you get some crud in the gas which is now lodged between the needle and its seat which is holding the needle valve open.

 

Thanks for the insight. My original pump did not have a space so I put this one on without a spacer also. Assuming the spacer changes the angle/pressure of thew trigger against the cam so it doesn't pump as hard? Off to buy a pressure gauge. I figured an even 2-bolt, part-for-part swap would be easy! lol. Should've known better by now...

You are going to need a fuel pressure gauge suitable for a carburettor system. Do not use a fuel injection pressure gauge because their accuracy at carb system pressures is poor. Measured at the outlet of the pump the pressure should be 1.5 - 3.5 psi according to the Volvo service manual. You will need a Tee fitting in the line to do the test. If the pressure is above 3.5 psi the pump is the problem. If the pressure is below; but, close to 3.5 psi it is probably still a problem.

There is a spacer between the pump and the block. There are different thickness spacers and you need to make sure that you have the correct spacer as that changes to position of the arm relative to the operating cam which alters the pump stroke. That said, even with the correct spacer others have reported problems with excessive fuel pressure. It seems like there might be a batch of incorrectly designed pumps floating around.

Measure the pressure. If it is above 3.5 psi and the spacer is correct you need to have a discussion with CVR about them fixing the problem. If the pressure is less than 3.5 psi, then I would look at your float needles. Specifically, when messing around with the piping did you get some crud in the gas which is now lodged between the needle and its seat which is holding the needle valve open.

 

Can I assume you’ve got the black plastic spacer correctly in place between the block and the pump?
How long does it take to leak when pumping into empty bowls, immediately or after the bowls have filled?

The pump “runs” (actually sucks) continuously; there is a small valve inside (#73580) which may not be working or installed incorrectly

From the Workshop Manual: “The pump is fitted with an idling device whereby the pump output ceases when a sufficiently high pressure has been reached in the float chamber.”

Diconnect line at float, run engine on gas in float bowls and get a sense of the output over time.
Pressure at fuel pump height = 1.5-2.5 lb/sq.in

 

This "spacer" seems to be the main issue. The car and original pump did not have one so I have no spacer on it now. Figured since it didn't have it, I wouldn't need it, but apparently the new pumps are stronger than the 60 year old ones! Just ordered a spacer. thanks!

 

What, no spacer?
Don’t waste your time with a pressure gauge…

 

With no spacer, that is almost definitely your problem. Too much pump. I was under the impression as well that a lack of spacer can also cause travel distance issues for the pump mechanism, damaging it or the cam.

 

love the pogging profile pic also.

 

lol. that's my google pic. I should post a pic of the car instead, eh?

 

Tim;

Welcome to this forum!

I'm with other responders...the replacement FuPu must be mounted with the Spacer...see also: SW-EM Fuel Delivery Components and Considerations

Cheers

 

Thanks! was a member here years ago but lost/forgot ny old account. Was out of the Volvo game for a while.

Tim;

Welcome to this forum!

I'm with other responders...the replacement FuPu must be mounted with the Spacer...see also: SW-EM Fuel Delivery Components and Considerations

Cheers

 

Oh very nice!

 

“…but apparently the new pumps are stronger than the 60 year old ones!”
Au contraire…

I would guess that, if someone hadn’t ****ed up your original pump by omitting the spacer, it might be still OK today, or at worst just need a new diaphram.

My ‘62 still with original spaced-out AC pump, with original diaphram.

 

Tim;

nNH makes a good point...without the spacer, the diaphragm was being "over-exercised" which undoubtedly contributed to its failure...

Cheers

 

Update: yup, spacer solved it. Thanks all for the help. Interestingly, the original pump definitely never had a spacer because the bolts were too short! I had to root around through my coffee cans to find some bolts that could hold the pump and spacer. Thought y’all might dig the other rides. My DD is the kei truck and the Vespa I converted to electric for sunny day commutes

 

Tim;

Great to hear it's sorted!

...I might even suggest that the "original FuPu" had a weak Non-Return Valve (or two), which is the reason it never built up pressure which overwhelmed the Bowlvalves (because this would be absolutely typical when running without a spacer!)...weak NRVs might also be accompanied by long cranking times (since the valves couldn't hold the column of fuel in the line to the carbs from falling back down...)...did you have long cranking times, after car was parked for more than a day or two?

Long cranking times are certainly typical after extended parked times when atmospherically vented Fuelbowls have dried to a great extent.

OK on the alternate transports...your Amazon even dwarfs the micro-truck! Have you ever seen the Italian Piaggio Apecar minitrucks?...talk about micro-trucks...!

Cheers

 

Yes, I did have long crank starts, whereas it started right up after sorting this all out. Decades ago I had a 164 that I never got running right but that was th only other carburetted Volvo I've owned. (I was a dumb kid and there was minimal internet, whereas nowadays I'm a dumb adult with access to the world's knowledge

Yes, I'm familiar with those three wheeled death traps! I could combine the Vespa with my truck to make one. lol. That little Honda Acty is by far the most reliable little thing I've ever owned and goes everywhere - except the highway.

 

An elderly Amazon, a kei truck and an electric Vespa. You be livin' in the transportation fringe zone my man!

 

I don't do "normal" real well