Morris Minor Owners Club

Hi All,
My Austin pickup has been off the road for a few months, finally got it through MOT (long story, dodgy garage). However it has since developed a missfire at high speed.

To cut a long story short I needed a new fuel pump for my saloon project so I bought an electric morris style pump and fitted this to my Pickup as I was going to be using this most often and put my old pump from the Pickup onto the saloon. Now when going about 70mph it will not pull up hills or go any faster (used to happily go 90, has a marina 1275 engine), it cuts out like it has a rev limiter, ease off the gas and all is fine again. Question is is this fuel starvation from a poor new pump? What flow rate should the pump provide to feed a 1275cc at 70+ mph. If not this what else could be the cause? I've checked mixture and points.

Cheers for your help

Matt

Question is is this fuel starvation from a poor new pump?

very & highly likely

What 1275 are you running that doesn't have a mechanical fuel pump?
a

Its a marina 1275 engine but the mech fuel pump has a blanking plate over where it should be. Anyone got experience of mech fuel pump? I like the idea but don't like the idea of having to crank engine over loads if stood for a while to get fuel to carb before any chance of starting.

It would be worth checking the fuel pressure if you have a guage to see if it can maintain a steady pressure + check the fuel lines aren't restricted in anyway. also you say its a morris style pump is it an su one as some non su pumps need to be a certain way up or they dont work very well they usualy have an up arrow on them somewhere (my brother in law did this on his A35 once as soon as he corrected it it was fine)

Mini's use mechanical pumps... if its a standard 1275 it should have no problems with either sort!

mattcmgb wrote:Anyone got experience of mech fuel pump?

Well, me Never had any problems whatsoever with them - and they'll be designed to provide enough fuel. As Matt says, grab a Mini one and your problems should be over. I assume your cam has the correct lobe to operate one, the Minor one does after all, and it never had a mechanical pump...

I believe the standard Marina/Ital one does... the one I removed from my engine certainly did

sounds like the pump, but check the fuel pipes are clear, and not perished on the inside.

Andrew

Why not just swap over the pumps you have and see if the problem goes away? Maybe just needs the filter in the pump cleaning. Pump should be able to deliver 1 pint in 2 minutes. Roughly equates to 15 mpg !!

Pump should be able to deliver 1 pint in 2 minutes. Roughly equates to 15 mpg !!

Yes but the pump test is with no back pressure from the float chamber valve, so the pump runs all the time. Try connecting a fuel flow gauge into a running Moggy, you will get quite a surprise at 30MPH on a flat road with a vacuum of 15hg

Of course - but if the car is using the fuel (indeed seemingly running short) then the float valve will be open anyway. If the pump can do 1 pint in 2 minutes there's nothing wrong with it!

Many thanks for your help, have swapped pumps and all is OK again.

Thanks again

Matt