Morris Minor Owners Club

Hi,
I want to change the oil in my dashpot for a lighter fluid. What is the best way to remove the existing oil? and how much oil should i fill it back up with?
thanks
Martyn

Take the dashpot off (3 screws) and withdraw the piston from the carb body and leave it upside-down to drain. Careful you don't damage the needle though as you take it out and put it back!

I want to change the oil in my dashpot for a lighter fluid.

Wouldn't that be dangerous? If you want to light your cigarrette whilst checking the oil and water, an zippo is probably better

Yes, very good Ray....

Martylemoo; 'I want to change the oil in my dashpot'.

Any reason why? Did you have problems last Winter when it was cold?

Martyn
What do you want to change it to, lots of us just use good old 20w50

I used to use 3-in-1 oil as recommended by a 'top tips' Minor article, but for the last few years I've used 20W/50. I've had no starting problems, even at temperatures as low as -5 degrees Centigrade. The reason for using a light oil was to ease low temperature starting. I guess 20SAE is fine in the South of England.

20/50 should be ok - The whole point of a multigrade is that it doesn't go as thick when cold and doesn't go to thin when hot.
Therefore a 20/50 should behavelike an SAE 20 in cold weather, (but is probably better when hot, ie. it still damps the throttle slide)

I use engine oil in the dashpot (Castrol 15/40) and I find it too thin as the throttle slide still opens quickly and for more comfort in a traffick jam, I'd prefer it to be slower.

just after a quicker opening throttle slide, the 1300 doesnt seem quite as responsive as i want and just something i thought i might try as i do not often drive in traffic.!! cheers guys

martylemoo wrote:just after a quicker opening throttle slide, the 1300 doesnt seem quite as responsive as i want

I don't think the dashpot oil is likely to be your problem. The oil just damps the movement of the piston. If you run without oil, under brisk acceleration you will feel & possibly hear the piston fluttering. Too thick an oil will just stop the vacuum lifting the piston. 20/50 is unlikely to overdamp it. I would check that you do not have too strong a damper spring, most do. Also check that the piston rim & the dashpost are squeeky clean (but don't use harsh abrasives). A slightly bent needle or a sticking one on a swing needle carb can dull response, as can a worn needle or jet, the jet particularly on a swing needle carb.

just after a quicker opening throttle slide, the 1300 doesnt seem quite as responsive as i want

I think Martylemoo is on about the 'throttle response' of the engine which IS affected by the oil, as well as the points you mention. Over the years I have tried loads of different oils in the dashpot of carbs attached to mostly tuned A-series engines and I found the best one (for response) to be the oil produced by SU (Burlen) themselves. I tried Penrite dashpot oil, but it's far too thick, as is engine oil (for tuned engines - but fine for standard ones).

Martylemoo, try to get hold of some proper SU dashpot oil from Burlen (I think they still sell it). Give it a whirl and see what you think. It worked OK for me.

cheers cam,
i will try and get some

Yes they do sell it
http://www.burlen.co.uk/