Hi everyone. My 850 is not running too well. It was ok after we timed her up, changed plugs, leads and filter as well as new petrol, but now it seems chocked. I have noticed there is very little oil in the dash pot. Would this be the reason?. And can someone tell me what the oil is for. I have ordered some oil from a local supplier but cant collect or a few days.

Thanks Mike

The oil is there to dampen the rise and fall of the piston in the carb. When you plant the accelerator, the piston will be dampened and won't rise immediately, this will richen the mixture and give a better response. A thicker oil will richen more, a thinner oil will lean out. Keep in mind that this also affects the fall speed of the piston, so it's not a matter of 'use a thick oil' or 'use a thin oil' - you need to match it to your car.

So, if it's carrying on when you open or drop the throttle, it can be the dashpot. It's filled to about half an inch from the top.

If it's idling funny, check your mixture screw under the carby. Wind in to lean off the mixture. Also make sure your choke isn't sticking, as that can happen.

Thanks irish

Ill let you know how I get on.
Mike

A lot has been written about "recipes" for dash pot oil. Proper SU oil is (was ??) straight 30 wt.

Ordinary engine oil 20/50 (or whatever) works fine. IME engines run "OK" even with no oil - but they will be a b%^$er to start...

I strongly doubt this is your problem..

Cheers, Ian

I find ATF (Dexron II or III) works well in most Minis. But when we had Barney (1293A+ with twin HS4s) it ran best in summer with NO oil in the dashpots.

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Hi guys, well finally got the oil, topped her up,, no difference. Stripped the carbi, altered the choke screw under the carbi, cleaned the plugs they were black with soot. I think it was choked up. Now runs pretty well, will see how it goes. Mike