Engien dies,when revved

Post by **beanpole** » Sat Oct 23, 2004 1:02 pm

Still having problems with moggy..

I have fitted an HIF38 , (from a Metro, and currently with the standard needle for the 1.0 Metro), fitted new rotor arm, (magnetic electronic ignition), new coil, new leads and new plugs.

Car starts okay on full Choke, and will rev but for only about 2 seconds, then dies, starts again okay, and ticks over, rev the engine and same again, just dies unless I quickly lift my foot off the accelerator, then the engine will just about recover and tickover until revved again.

Fule pump ticks until float full then just the odd tick when turning over.

Even on full choke, the engine does not seem to be a rich as it should be, ie not very fast tickover and no (chugging form overfueling), so I am guessing weak mixture somewhere..

Surely just the standard needle from the Metro is not the culprit, I am waiting for an AAA needle.

Steve

Post by **Alec** » Sat Oct 23, 2004 3:01 pm

Hello BP,
like most S.U.'s, set the jet down two full turns of the adjusting screw from flush with the bridge, ensure the needle locating sleeve is flush with the base of the piston. Even with the wrong needle you should get some reasonable response. Is the piston lifting in the damper chamber when you try and rev the engine?, it should.
Another long shot, but it happened to me on a Triumph 2.5 with twin HS4 S.U.'s. It just would not accelerate, just spluttered as though it was weak. I went thriugh the carburettors with a fine toothcomb, nothing. In desperation I wound the distributor way too far advanced, and bingo, with a little more trial and error it went like a train. All I can assume that the markings were wrong as there should have been no way that it should run with about 30 degrees static advance.

Alec

Post by **beanpole** » Sat Oct 23, 2004 5:00 pm

Thanks for the help , re-stripped the carb down, cleaned and checked everything, then re-assembled. This time I made sure the mixture screw positioned the jet to a couple of mm below the bridge.

Started her up and everything seemed to run a Lot better, screwed the mixture screw in even further and now runs very sweet.

However I have had to screw in the mixture screw quite a lot, so I possibly have a combination of the wrong needle and an air leak, but at least she runs very well indeed now.

Steve

Post by **Cam** » Sat Oct 23, 2004 8:56 pm

Steve, have you got the HIF38 breather connection blocked up or open to the air?

Post by **beanpole** » Sun Oct 24, 2004 12:07 pm

cam,

Breather is blocked off, vac connection is not leaking.

Can't for the life of me think where the air is getting in, but at least the mixture adjustment is compensating very well.

Steve

Post by **Cam** » Sun Oct 24, 2004 12:13 pm

but at least the mixture adjustment is compensating very well.

Yes, it did that on mine at tickover/low revs, but the power REALLY dropped off at high revs and it started popping (REALLY leaning out) and I had a VERY rich needle in it too!

Post by **Alec** » Sun Oct 24, 2004 12:49 pm

Hello all,
a little point about S.U. needles, the idle dimension is virtually identical whatever the needle (within it's group size, i.e. 0.090", 0.100", 0.125" etc.). So any needle should give near correct idle mixture at the standard two turns.

Alec

Alec