Do I have the function of the waxstat jets correct?
As the engine warms up the jets weaken the fuel mixture?
When I reach motorway speeds, the cooling system seems to struggle and engine lacks power.
Could the jets be the issue?
After a long run the plugs come out very pale in colour.
Running around town(no choke this time of year), plugs verging on black.
Any pointers appreciated.
waxstat jets?
- whydidistartthis
- TDC Member
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- Joined: Sun Jan 03, 2010 8:39 am
- Location: Maidstone, kent
Re: waxstat jets?
Waxstats are the devil's invention. My advice is ditch them for normal jets, or at least remove the wax cartridges and replace them with two 2p coins. My car would start and run beautifully then after driving perfectly for a couple of miles (ie once the engine has warmed up) it started to lose power and had all the symptoms of fuel starvation. Eventually it could only crawl along flat out at 20 mph. Ditching the waxstats made a complete cure.
They must have worked when new so I can only suppose it is modern petrol that causes the problem.
They must have worked when new so I can only suppose it is modern petrol that causes the problem.
Mike
(1969 MGB GTV8, 1977 Dolomite 1850HL, 1971 MGB roadster now all three on the road)
(1969 MGB GTV8, 1977 Dolomite 1850HL, 1971 MGB roadster now all three on the road)
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- TDC Member
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Re: waxstat jets?
Sorry to be picky. It is 2x1p coins.
Otherwise, I could not agree more!
(and I would suggest the penny conversion is the better/simpler solution, and somewhat cheaper)
Clive Senior
Brighton
Brighton
Re: waxstat jets?
You're right Clive. Sorry about that.
Mike
(1969 MGB GTV8, 1977 Dolomite 1850HL, 1971 MGB roadster now all three on the road)
(1969 MGB GTV8, 1977 Dolomite 1850HL, 1971 MGB roadster now all three on the road)
- whydidistartthis
- TDC Member
- Posts: 474
- Joined: Sun Jan 03, 2010 8:39 am
- Location: Maidstone, kent
Re: waxstat jets?
Thanks.
Sounds like a starting point. See if I can find out how to do it. I know the basics. If not pull one apart and work it out.
Sounds like a starting point. See if I can find out how to do it. I know the basics. If not pull one apart and work it out.

Re: waxstat jets?
Have a look at this YouTube video. The guy takes a long time to get to the business but here's what to do. He doesn't have any British pennies but that's what you should use, two pennies per carb. He makes the error of putting the spring in the wrong place at first but gets it right eventually. I put my removed waxstat in hot water and was amazed how much it expanded pushing the jet right up, which accounts for the excessive leaning of the mixture.
https://www.youtube.com/watch?v=nIg-IEeDoL0
https://www.youtube.com/watch?v=nIg-IEeDoL0
Mike
(1969 MGB GTV8, 1977 Dolomite 1850HL, 1971 MGB roadster now all three on the road)
(1969 MGB GTV8, 1977 Dolomite 1850HL, 1971 MGB roadster now all three on the road)