11 replies to this topic

[Ian-A]

Hi, just got a couple of questions regarding fitting a new mechanical fuel pump (1275 A+ engine).

1. I'm guessing the pump is gravity fed so I assume I need to clamp off the fuel line from the tank to the pump before removing the 2 hoses on the pump?

2. Are there any tips for getting the new pump arm installed properly so it sits correctly on the cam (i.e. the arm is against the cam and not behind it)? I'll be doing it with the engine in car so won't be able to see how the arm is sitting. How do I know it is in the correct place?

[alpder]

Not one of your questions, but... make sure you've got the plastic spacer.

 

I initially also worried about the arm going in the wrong place, but as the pump is slid onto the studs it can't really miss.

 

Bigger problem is the way the outlet pipe points: makes it not easy to run the fuel pipe and keep it away from the hot exhaust - with risks of fire and/or vapour lock. I sleeved my pipe in "Fire Sleeve Braid Flame Heat Reflective Shield - Size 12mm" https://www.ebay.co....ar=564626684994

 

(by the way mine was a van, so I can't answer (1)).

Edited by alpder, 29 August 2025 - 05:14 PM.

[mab01uk]

Minispares say:- "When fitting make sure the pump lever is sitting on the cam lobe, not to the side."

https://www.minispar...ars-and-all-998

 

 

 

[nicklouse]

Ok pumps. Back in the day there were issues with there being different sized plastic spacers and if you did not use the correct one for the pump you either broke the arm or it did not pump.

 

What ever pump you get fit it as per its instructions do not presume it a a direct replacement.

 

then there are the pumps with the plastic pads that are meant to run on the cam. Nope nope no. Not suitable at all.

 

yes you will need an empty tank or clamp the fuel hose.

[Spider]

In regards to the arm and cam issue, it's actually pretty hard to mess that up.

[Lplus]

Hi, just got a couple of questions regarding fitting a new mechanical fuel pump (1275 A+ engine).

1. I'm guessing the pump is gravity fed so I assume I need to clamp off the fuel line from the tank to the pump before removing the 2 hoses on the pump?

2. Are there any tips for getting the new pump arm installed properly so it sits correctly on the cam (i.e. the arm is against the cam and not behind it)? I'll be doing it with the engine in car so won't be able to see how the arm is sitting. How do I know it is in the correct place?

1 - depends on the fuel level in a saloon tank, the van/estate/pickup tank is lower than the pump - UNLESS you have to park on a steep hill facing downwards

 

2 - keep it as straight as possible until you have the bolts in and finger tight and you should be ok.  It may have studs which makes it easier.

[Ian-A]

Not one of your questions, but... make sure you've got the plastic spacer.

Is that this that sits between the engine block and pump? https://www.minispar...er-block-gasket

[alpder]

 

Not one of your questions, but... make sure you've got the plastic spacer.

Is that this that sits between the engine block and pump? https://www.minispar...er-block-gasket

 

Yeah. Not visible in MS's picture is that the plastic spacer is quite thick. Probably some listings on ebay which'll have better images.

[Ian-A]

then there are the pumps with the plastic pads that are meant to run on the cam. Nope nope no. Not suitable at all.

Is that the plastic end on the arm you are referring to on this pump? https://www.mgocspar.../4236/4255/4257

I'll avoid them but out of interest what is the problem with them? Could the plastic bit come off in the engine? Or could it get chewed by the cam?

[nicklouse]

 

then there are the pumps with the plastic pads that are meant to run on the cam. Nope nope no. Not suitable at all.

Is that the plastic end on the arm you are referring to on this pump? https://www.mgocspar.../4236/4255/4257

I'll avoid them but out of interest what is the problem with them? Could the plastic bit come off in the engine? Or could it get chewed by the cam?

 

 

[Ian-A]

Looks like most aftermarket ones have the plastic cap on the end of the arm. Is it only the Berlen/SU Carbs ones that have a metal arm with no cap?

[nicklouse]

No idea. But they never had anything on them aftermarket or original.