B18 B engine

[Salop Farmer]

I have noticed the longer the gap between runs in my B18B engined 544 the longer the cranking time on the starter motor before the engine starts. In other words if I start the car on a daily basis very short cranking time. But if I don’t start the car for 3 weeks say, I would have to crank for 5 or more seconds before the engine starts. I suspect it’s a fuel pump issue and maybe normal for the twin SU set up! What do other owners think? Thanks in advance.

[Rustinmotion]

Originally Posted by Salop Farmer

I have noticed the longer the gap between runs in my B18B engined 544 the longer the cranking time on the starter motor before the engine starts. In other words if I start the car on a daily basis very short cranking time. But if I don’t start the car for 3 weeks say, I would have to crank for 5 or more seconds before the engine starts. I suspect it’s a fuel pump issue and maybe normal for the twin SU set up! What do other owners think? Thanks in advance.

Fuel is evaporating in the fuel bowls so it takes a few cranks to fill them back up, an electric pump would prime the bowls before starting to crank the engine

[Austinvolvo]

I rarely drive mine and had the same problem with both an 1800 and a 544. I installed electric fuel pumps back at the tank and problem was solved. I'm not sure if its really required but I put a check valve in parallel with the pump so that the mechanical pump can draw directly from the tank and not have to pull through the pump. On the 544 I used the existing momentary contact (pull toward the driver...a high beam flasher I guess) for the switch to run the mechanical pump, which makes it harder to accidentally leave it running.

Dean

[Ron Kwas]

SF;

Carb Fuelbowls are atmospherically vented, so some level of evaporation does occur, but this is no reason to install a different Fuel Pump IMO. Cranking for a few seconds while the fuelbowls are refilled also builds oil pressure and preoils the works (and without a power stroke!)...not such a bad thing...

See also: http://www.sw-em.com/su_carbs.htm#Long_Cranking

Cheers

[Salop Farmer]

Thanks for all the comprehensive replies. After reading all Ron’s add ons I’ve decided to live with the mechanical Volvo fuel pump and a little extra motor cranking!

[Othen]

I’d agree with Ron’s explanation and the OP’s conclusion. My Amazon with a B18D motor is exactly the same.

[Derek UK]

If I leave my Estate for several months in the winter or anytime of the year, I expect to have to churn it for 20-25 seconds on full choke. If I have parked for a few hours at a show I can just reach in, turn the ignition on and press the start button. It will normally go straight to a slow tick over. Sometimes too slow and needs that first pre jet move of the choke.
With SU's you must resist pumping the throttle pedal for virtually all starts. If you have somehow managed to flood it, full throttle and back off the pedal steadily as it fires. Zeniths can take a pump as they have an actual accelerator pump.

[Groundes-Peace]

I believe there can be a benefit, with a mechanical fuel pump requiring a little extended cranking after a car has not been run for quite a while.
In the cranking time the oil is being forced around the slow rotating of the engine's internals before it fires, hence providing some early lubrication to dry surfaces.

There is a video on Ian Tyrell's website of the benefits, although he in the main is talking about high end performance classic cars ( Ferrari, Lamborghini etc), but the same thing applies.