? Fuel starvation and hello.

[issigonis]

Hello I'm new to this forum and my problem is using a 1300 engine with standard 1098 carb and exhaust . All is well ubtil powering up a hill at 60+mph when a misfire develops which rapidly improves if I back off and carry on with a lighter foot. Is it likely that the electric petrol pump can't keep up or is the little carb just not able to deliver the goods? I have to say that generally it pulls pretty well. Noisy stainless steel exhaust tho but I have alraedy read about that one.

[Kevin]

60+mph uphills that sounds a pretty good speed to me I am not sure what would be causing the problem at speed only but the pump can cope with a much bigger carb than the standard one up to 1 3/4" does not cause problems.
A 1275 engine should really be run with an 1 1/2" carb not an 1 1/4" you can still retain the standard exhaust and exhaust side of the manifold, you just need an alloy inlet manifold and cut of the cast inlet part off the minor manifold.

[d_harris]

60+mph uphills that sounds a pretty good speed

From a 1300? we can do that with the 1098!

[Kevin]

we can do that with the 1098!

Does Southampton have any proper hills as I would like to see your Trav accelerating up a hill at those sort of speeds.

[rayofleamington]

accelerating up a hill

nobody said accellerating ;-)

I ran a 1275 with a standard 1098 carb, manifold and exhaust and could do mild hills at 80 where the 1098 had struggled to maintain 60.
I would guess you need a different needle as that is often the case for missfires.
If it is fuel starvation, that gives different symptoms - like 1 second running 1 second not running 2 seconds running, 2 seconds not running and so on.
One of mine gets fuel starvation if I drive for more than a minute above 75mph - it's a real pain if you were trying to pass someone

[issigonis]

That sounds like it .1 second running and then spluttering. I do have the original ital carb but that has a twin down pie which would mean another exhaust ant the air filter is a very odd looking affair with a 2 way air inlet which has a valve of some sort in it. I assume it either sucked in hot or cold air when it was on the ital.

[rayofleamington]

For fuel starvation - check the inlet to the carb - sometimes you can get a build up above the float needle which limits the flow of fuel into the carb, and also check that the level is high enough - if that's ok I would be tempted just to try another carb as standard ones are ten a penny.

The petrol pump idea is also a possibility, but I don't know how likely it is. On the car where I had fuel starvation I just avoided trying to drive at 80.