Replacing mechanical fuel pump with electric on 2.25 petrol engine

Quote:

---

Originally Posted by mox

Remember with this setup, what will also be needed is an appropriate way to run the electric fuel pump before and while starting so fuel is available before oil pressure build up. Like part of 'watchdog' setup I have on tractors and have yet to get around to installing on Land Rover 300Tdi's. Includes oil pressure switch which has some adjustment that switches on when oil pressure is about 10 psi or above. (Opposite of the type for low oil pressure light which comes on while there is no or low oil pressure) On older injector pumps without an electric solenoid cutoff, have a fuel solenoid between secondary fuel filter and injector pump. Also a push button which is held in to keep the fuel solenoid open when starting until oil pressure builds up. If oil pressure drops below what switch opens at for any reason, is no power to fuel solenoid which then closes and stops engine. Basically this is protection against 'blowing up" motor from running out of oil. A push button would also be the simplest relatively "idiot proof" setup for starting a motor with electric fuel pump fitted. ie Not left switched on unintentially.

Worth noting other parts in my "watchdog" setups are 105 degree temperature switches which are closed at lower temperatures on cylinder heads. Power to fuel solenoid also goes through one of these. So if head gets to 105 degrees for any reason, no power to solenoid and motor stops ( when solenoid before and not in injector pump, more slowly as it starves for fuel.) With push button (or an emergency on of switch which idiots may leave on and defeat protective function), the motor could be kept running for a short time as head should tolerate significantly more than 105 degrees before damage occurs. eg To drive vehicle or machine to a suitable parking spot nearby. Is important to note that this setup offers protection against the head overheating from any cause. Also, if something goes wrong with the protection setup itself such as a wire becoming disconnected, motor stops. Some other safety devices offer only limited protection, eg against low water level. Also with some, if malfunction such as wire coming off and power is needed to operate warning device or stop motor, it will not provide protection it is supposed to.

---

Hi what about going the other way? I have a 2.5 defender 90 petrol in a series 1 . Can i do it and if so how ?

make sure the fuel pump is under 4psi or put a pressure regulator in the line or you will have issues.

if using a "Facet" style fuel pump you need to put it down as low as you can as they push really well but do not create much suction.

cheers

Quote:

---

Originally Posted by whitehillbilly64

Hi John.
what type of pump did you get. Link Please.
What is your reason for changing from mechanical pump ????
Kits are cheap and pump easy to service.
What do others suggest.
Thanks.

whitehillbilly

---

Shane, I am finding that if I don't start the landy for a couple of weeks, I get an airlock between the pump and the filter, and no amount of cranking will give me enough fuel to start. I have a weber carb, so maybe better with other carbs. I thought I would try a cheapie pump first to see if it solves the problem, so I bought a New Electric Fuel Pump For Motorcycle Low Pressure 12V Carburetor FP-02 ATV | eBay but I haven't installed it yet.

Cheers,
John

Quote:

---

Originally Posted by 4bee

I fitted an SU electric pump that I had on the shelf & bolted it to a chassis cross-member & just teed the suction & supply pipes in. It is handy, because when my 2A stands without regular use the check valves in the mechanical pump leak back & it loses it's prime. Then the engine has to be turned over for long periods to get fuel to the Carby. The Hand Primer is such a **** of a thing to get to & operate IMHO.

So a permanent cable from the pump is applied to the battery terminal to energise the pump until it fills to the carby. Starts fine & even better after replacing the press button starter switch. Now instantaneous.

Seems these mech. pumps are prone to losing prime with leaky check-valves & mine has been overhauled twice in my ownership so I gave up & use the SU when needed.
The rest of the time during normal operation the mechanical pump does the work.

Job done.

---

So you put the elctric pump in parallel to the mechanical ? I like the idea of keeping both.

Thanks
John

Yes John, with a Tee piece each side of the Mech pump. I know when the SU is working because it reverberates through the chassis despite the rubber isolators but as it is used only briefly & when stationary, after the engine has started it is of no real consequence.

It is a bit tight-ish down there but is quite do-able without throwing the SU across the shed & with minimal swear words but make sure you use good quality fuel injection hose & clamps.

Cool !! I will definitely go the dual pump approach.

So, did you consider putting them in series, so tank->mech pump->electric pump-> filter-> carb ?

I guess that means you can't turn off the elec pump when engine is running :-)

Just thinking out loud ....

Cheers
John

No, I didn't even consider that as I thought there could be a problem with either of the mech pump check valves (there are two in there) operating against the flow. In my case using it as an ad hoc thing it wouldn't really happen, but down the track something could.

Interesting thread - I have been running Series 2/2as on and off for almost sixty years (current one for nearly thirty), and have never had an issue with the mechanical pump that did not have an easily found cause and was easily fixed. Most commonly a small air leak on the suction side of the pump, often the gasket on the water trap, but I have had a hair (looked like) under one of the valves, and on another occasion a broken valve spring.

In the case of a vehicle left standing for long periods, about a minute with the hand primer is usually enough.

In the unlikely event of fitting an electric pump, I would fit it in line with the mechanical pump and with an on/off switch, to use it only for priming the mechanical pump.

the other big advantage i found with the electric pump was no more fuel vaporising in the fuel lines...

but thats more a worry with Holden powered units

That is why I bought the SU years ago to fit to the engine bay of a Hi-Ace with a high engine cowl I found fuel vaporised & took a while to start.

Wasn't high on the to do list at the time & never was fitted to the Hi-Ace but sat on the shelf until it went into the S2 & in the meantime was temporarily fitted into a Morris Minor hi-lite to keep it running for a friend until the other was repaired.