jordan_meakin Posted January 2, 2017 Share Posted January 2, 2017 So, has anyone actually ever found a solution to poor hot starting caused by petrol evaporation in the carb? Quote Link to comment Share on other sites More sharing options...
Jon White Posted January 2, 2017 Share Posted January 2, 2017 Electric fuel pump Quote Link to comment Share on other sites More sharing options...
lo-fi Posted January 3, 2017 Share Posted January 3, 2017 What carb are you running? My twin strombergs are a devil for this, and run rich when the under bonnet temperature gets above a certain point. I've come to the conclusion a little fan to move some air over them when not moving is about the only way to deal with it. I'm running an electric fuel pump and regulator - it doesn't make any difference. Quote Link to comment Share on other sites More sharing options...
jordan_meakin Posted January 3, 2017 Author Share Posted January 3, 2017 Mine's a Zenith. I rebuilt it with new gaskets and heat spacer things but still no good. I heard mixed reviews on electric pumps... Running isn't affected, just hot starting. Always does start but can be a bit embarrassing as it turns over! Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 3, 2017 Share Posted January 3, 2017 A good electric pump will always be good, all modern cars use them so they must be reliable... Just avoid the rubbish ones and it will all be good Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted January 3, 2017 Share Posted January 3, 2017 I've previously had great succes with covering a plate with powerwrap and fitting it between the manifold and the floatbowl. I did however close off the hole in the exhaust manifold at the same time (the hole where it connects to, and preheats the intake manifold. It helped a lot but can't tell you which part did the most. You could also powerwrap the Whole downpipe and exhaust manifold to remove a lot of heat from the engine compartment Quote Link to comment Share on other sites More sharing options...
tacr2man Posted January 21, 2017 Share Posted January 21, 2017 (edited) The answer is leave the mech pump on and fit a facet lecky pump back by the tank Wire it to switch just prior to start switch on lecky pump this will overcome vaporizing in either mech pump or carb . When running switch of lecky pump . This gives you a standby pump if mech pump fails as well , same sytem is used on all piston engined aircraft , I have done this mod to several petrol engined vehicles . http://www.ebay.co.uk/itm/Red-illuminated-LED-Toggle-Switch-With-Missile-Style-Flick-Cover-Car-Dash-12V-/262254582103?hash=item3d0f975957:g:zBYAAOSwnDxUlv6g used this type switch to save inadvertently leaving on Edited January 21, 2017 by tacr2man 1 Quote Link to comment Share on other sites More sharing options...
jordan_meakin Posted January 21, 2017 Author Share Posted January 21, 2017 That's really useful but I have no idea what I'm doing with electrics! My friends always find it quite shocking... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 21, 2017 Share Posted January 21, 2017 Electric pump would only need a fused wire to be taken from the ignition live (white) wire that goes to the coil. My solution was a V8 with fuel injection Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 22, 2017 Share Posted January 22, 2017 21 hours ago, jordan_meakin said: That's really useful but I have no idea what I'm doing with electrics! My friends always find it quite shocking... That pun deserves a yellow card! Quote Link to comment Share on other sites More sharing options...
jordan_meakin Posted January 23, 2017 Author Share Posted January 23, 2017 On 22/01/2017 at 9:29 AM, Snagger said: That pun deserves a yellow card! Haha, thought no one had noticed!! Quote Link to comment Share on other sites More sharing options...
Quagmire Posted January 24, 2017 Share Posted January 24, 2017 On 21/01/2017 at 9:23 PM, FridgeFreezer said: My solution was a V8 with fuel injection This also improves the functionality of any cabin heater arrangement too! Quote Link to comment Share on other sites More sharing options...
missingsid Posted January 24, 2017 Share Posted January 24, 2017 On 21/01/2017 at 10:06 AM, tacr2man said: The answer is leave the mech pump on and fit a facet lecky pump back by the tank Wire it to switch just prior to start switch on lecky pump this will overcome vaporizing in either mech pump or carb . When running switch of lecky pump . This gives you a standby pump if mech pump fails as well , same sytem is used on all piston engined aircraft , I have done this mod to several petrol engined vehicles . I kinda get the point on a light aircraft but not on a car, by all means leave the mechanical pump in the block and pipes available for backup but if you fit a lecky pump then use this as he main. Why faf about with turning it on and off when it is a better pump than a mechanichal diaphram pump anyway? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 24, 2017 Share Posted January 24, 2017 Indeed, more points of failure, just use the electric and be done with it. The whole 'mechanical is more reliable than electric' is a total myth. Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted January 25, 2017 Share Posted January 25, 2017 I doubt an Electric pump will solve all your issues, my S1 was fitted with one from the factory and still had the problem. In some instances it's actually worse, as the hot starting issue usually is caused by the fact that the engine has to start in a way too rich environment because the intake is filled with hot fuelvapour. And especially if your carb has an acc. pump, because then you'll squirt in even more fuel when you go to open the throttle which in turn is necessary to start the already very hot engine filled with fuel. In my experience (and I have learned it the hard way sadly) the best way is to make that carb cooler. Quote Link to comment Share on other sites More sharing options...
Snagger Posted January 25, 2017 Share Posted January 25, 2017 The whole point of having both on aero-engines is to have two independent pumps running from separate power sources, so the mechanical pump will work if the aircraft has an electrical failure and the electric pump can prime the unstarted engine as well as back up the mechanical pump at critical times (low altitude and aerobatics, mainly). Having both on a car is no problem, but not essential like it is in an aircraft. It's not a direct comparator. Quote Link to comment Share on other sites More sharing options...
jordan_meakin Posted January 25, 2017 Author Share Posted January 25, 2017 Mine's a Zenith. Refurbed it which solved a multitude of sins, replacing all gaskets and replaced the anti-heat block but didn't solve the evaporation. Did anyone have one new from the dealership? Did LR not acknowledge this problem? Do other carbs suffer it too? Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted January 26, 2017 Share Posted January 26, 2017 On 25/1/2017 at 9:41 PM, jordan_meakin said: Mine's a Zenith. Refurbed it which solved a multitude of sins, replacing all gaskets and replaced the anti-heat block but didn't solve the evaporation. Did anyone have one new from the dealership? Did LR not acknowledge this problem? Do other carbs suffer it too? I think, back then it was just a part of owning an Automobile, a long with basic knowledge of how to clean and adjust your Points, and remove condensation from your dizzy. Nowadays you frantically browse through your touchscreen in the center console to find an app to tell your dealer the car needs to be picked up.. Seriously though, all vintage cars, motorcycles and tractors I've had/come across have suffered from heat soak one way or the other, some worse than others. The problem on cars/lorries/tractors at least is that the intake is often heated by the exhaust to get proper atomization of the fuel. Sounds very daft now, but maybe it was necessary with the fuel quality back then? I don't know but there must be a reason why so many did it, and that it doesn't seem necessary these days. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted January 28, 2017 Share Posted January 28, 2017 Vapourisation is a common theme that affects v8 powered rover P6's - in this case the cam driven pump has to pull fuel quite a long way forward from the tank, and the fuel line runs along the side of the block just above the sump to the pump so is in a nice warm environment. The theory on the Rover forums is that it was never really a problem back when the cars were new, but that the addition of Ethanol in modern fuels makes it worse. On my car, back when it was carbed I fitted a facet pump to the rear of the car pushing fuel forward to the engine bay(rather than pulling) and deleted the mech pump entirely. I never had any vapourisation issues at all after that. I think having a carb with a return to the tank and an electric pump is the best way to avoid vapourisation - the circulating fuel acts as a coolant for the carb and stops it getting hot enough to vapourise. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted January 30, 2017 Share Posted January 30, 2017 Putting an inline filter in the return can help with a bit of back-pressure, also lets you see if the returning fuel is liquid or fumes. Quote Link to comment Share on other sites More sharing options...
tacr2man Posted February 2, 2017 Share Posted February 2, 2017 (edited) The op was asking for a solution , that is what I posted , having used on various vehicles for over 40 years the info regarding aircraft was just an interesting ( I thought ) aside from a similar set up that i came across when flying . Putting an electric pump in circuit pushing from near the tank as mentioned by subsequent poster is most efficacious , where you have a built in backup ie a mech pump left in situ , with an electric pump select-able has to be an improvement over having a single system Just as I have dual battery system so I can switch in an instant jump start standby . The old 6 'P' s. The flow and return system was used on RV8 several models also ' Edited February 2, 2017 by tacr2man Quote Link to comment Share on other sites More sharing options...
jordan_meakin Posted July 17, 2017 Author Share Posted July 17, 2017 So, I'm going to fit an electric pump. Any recommendations on which? Any advice on the best way to wire it up? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted July 17, 2017 Share Posted July 17, 2017 As above, Facet red top (it is what most of the luddites that do racing on carbs use), with an ignition live switched, fused relay. Quote Link to comment Share on other sites More sharing options...
Quagmire Posted July 17, 2017 Share Posted July 17, 2017 Bowie beat me! My 2.25 powered 90 was fitted with the equivalent of one of these from the factory: http://www.glencoeltd.co.uk/facet-fuel-pumps/facet-cylindrical-pump-12v-24v/ you only need the basic spec version. The pump has done zillions of miles with no issue, infact it lives on as a low pressure pump feeding the swirl pot on my daily. Here's a copy of the Facet on Paddocks. http://www.paddockspares.com/prc3901-fuel-pump-ecternal-electric.html Quote Link to comment Share on other sites More sharing options...
jordan_meakin Posted July 17, 2017 Author Share Posted July 17, 2017 Thanks guys. My knowledge of wiring is pants. Where should I take the + feed from? And is the - simply an earth? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.