Excessive fuel - it drinks like a fish!

[markhunt]

Right guys, recent engine rebuild, all well and good, but its drinking fuel like i'm made of money! Any thoughts? Also, whilst it seems to run OK (a wee bit lumpy - but its marginal), it does seem under powered - connected to the heavy use of fuel maybe?

Thoughts, comments, observations as always really appreciated.

Mark

[Gresley]

Sounds like the timing could be out for one thing. Are the mixtures OK?

[martin]

Hi Mark, is petrol running out of the overflow at the front of the engine ? Lumpy usually means rich, all things being equal. Were the carbs set up, or simply replaced after the rebuild ? Martin.

[markhunt]

Carbs just put back on after engine work. Have checked timing and its bang on, so do you reckon its mixture and if so what's the best i.e. easiest method for a non technician like me? Mark.

[martin]

To be honest Mark, your best bet would be to get them sorted by somebody who has experience of Strombergs, but if you fancy a stab at it, the section in the Haynes manual is very good, but do be certain you follow ALL the procedures, missing one out will negate the next one. Good luck, Martin.

[Ian Durrant]

Heavy fuel consumption is most commonly caused by the needle valves in carburettors that have been stored. might be gummed up or just dirt in the seat.

Another cause is non functional vacuum advance, this means the engine is not timed right at light throttle such as in motorway cruising so you effectively have your foot down a lot more to maintain speed. check your vacuum advance isn't leaking by sucking on the pipe, you should be able to get a vacuum and that vacuum should hold.

[pcoleman]

jf you have a local guy with a rolling road i would have it set up dynamically, the savings in fuel costs will go towards the set up costs.had mine done as the running was pants with lack of power and urge and the difference was absolutely stunning, wish I'd had it done years ago

[richardthestag]

how much is it drinking?

Also a new engine will be tighter and probably use more fuel as a result.

Else what they said ^^^ check carb setup. are you running points or electronic ignition? Is the vacuum advance connected? Is the small vacuum connection on the front of the carb pedestal attached to the airbox or blanked off?

Lastly and probably way too obvious but the brakes are free and not binding I guess?

[markhunt]

how much is it drinking?

Also a new engine will be tighter and probably use more fuel as a result.

Else what they said ^^^ check carb setup. are you running points or electronic ignition? Is the vacuum advance connected? Is the small vacuum connection on the front of the carb pedestal attached to the airbox or blanked off?

Lastly and probably way too obvious but the brakes are free and not binding I guess?

put £40 in the other day and it did no more than 80 t0 100 miles. Electronic ignition, vacuum is connected at both ends and the other pipe ius connected to the air box, breaks are free.... I like the idea opf getting it set up on a rolling road, can anyone erceommend one in Gloucestershire (Berkeley)? Mark

[Malcolm C]

Mark
Just down the road from you in Thornbury
Lots of car clubs use them
Interpro Automotive Ltd 01454412777
16 Walker Way,
BRISTOL,

[martin]

put £40 in the other day and it did no more than 80 t0 100 miles. Electronic ignition, vacuum is connected at both ends and the other pipe ius connected to the air box, breaks are free.... I like the idea opf getting it set up on a rolling road, can anyone erceommend one in Gloucestershire (Berkeley)? Mark

Sorry, I can't Mark. If you do go for a rolling road setup, be sure you tell them the rev limit they must not exceed, they often bomb them up to 7000 rpm ! Martin.

[redstag]

I would check to see if the chokes are sticking on for any reason. Cable adjustment/fitting maybe?

Pete

[markhunt]

Thanks Malcolm I'll give them a shout - how did the trip go? Mark

[Moraystag]

Mine was a bit the same, liked a gallon or two. Having taken it , on two previous occasions to so called specialists to have carbs, timing etc set, it came back more or less the same, and failed on emissions 2 years on the trot. I was charged 125 & 140 quid for the pleasure
Finally found a guy this year ( the 3rd year of ownership ) who deffo knows his stuff. He used the old SNAP ON crypton tuning device and diagnosed various faults, one of which was the vacume advance. Bought a new vacume advance from J.P. and had it fitted by the smart fella last month. Had it on the rolling road, and everything is 100 % better and fuel consumption dropped considerably. Emissions 2.2 and unburned fuel 120 ppm, I think the limit is 1200 ppm. He gave it 3 runs on the rolling road, and although he said it was slightly harder to get an accurate reading in an auto, why I have no idea??, we averaged out 135 HP according to the print out..6000RPM. Scary stuff, especially when I had a few intermitent puffs of smoke on the first run. None on the second & third, blew the carbon build up to kingdom come he said as my ass was collapsing.
Oh and the smart fella, also showed me on his tuner that the alternator was ready to pop it’s cloggs. It did 2 x weeks ago LOL.
My point here is, make very sure you know the person undertaking your setting up process really know’s what he’s doing, otherwise just give your money to the wife as it’s wasted otherwise.
Mike