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ZS bad performance problems.

skikir

Jedi Hopeful
Offline
I just put the original ZS carbs back on the TR. They seem to idle fine but under load they lose power. At cruise they seem fine but just off cruise it starts bucking. I put 30wt oil in the dash pots for starters. Timing seems OK. I haven't tried anything yet since it was getting late when I got back from first test last night. Anyone got some quick ideas to start with?
 
Don't have the answers but I do have a similar problem.
My TR6 with orig ZS carbs was running VERY rich (DPO) so I got the special adjusting tool and leaned them right out. The smell of raw gas has gone now and the car generally runs well except under heavy acceleration it bucks occasionaly as if it's cutting out momentarily, seems to improve with a hot engine.
I think my mixture is just too lean now.
Going to experiment this weekend.
 
I had a set of DGV32/36s on for a while. This car was off the road for about 18 years so I put the webbers on because I knew their condition (they had their issues but I knew what they were) but I didn't know what kind of crap was in the originals until I got around to clean them and suprisingly they did not look too bad when I did. I think I'll try a lighter weight dash pot oil for starters, but I've run 30wt in my other TRs and they have not run that bad. I'm wondering if I have a weak spark and it's blowing out under load? I have an Alison HO coil and electronic system on my parts car I have to get around to transfering over. Since it does it at all speeds and idles nicely and reves fine and there are no vacuum advance on it, I can't see timming being out that much.
 
Please tell me you changed out the diaphragms after 18 years!!!! You may need to renew the spindle seals as well.

Thick oil in the dashpots will richen the mixture on acceleration. I did a bunch of experimentation with both straight weights and multi-vis. Naturally I ended up with the fussy mixture of 1 part 15w-50 to 2 parts 10W-40. I like the multi-vis because it won't be too rich on acceleration when everything is cold, and it stays thicker when everything is warm on a 95 deg F day. Hey - it was something to do

/ubbthreads/images/graemlins/driving.gif
 
The diaphrams look good and supple. The spindle seals seem good also. I put some light oil in the dash pots and tools in the passenger seat. Car ran worse. So I stopped under a street light and advanced the timing by ohh...that much. Ran much better. Seems a little lean on acceleration now but at least it accelerates! Need to go back to the 30wt oil in the dash pots. Wonder if I got the timming right was because the light was in the parking lot of a church?
 
Ha ha. Just try not to make adjustments next to a graveyard...

Take a good drive, then check the spark plug color. That will tell you if you're overall rich or lean. Of course you sync'd the carbs. The whole process is iterative - drove my last wife crazy - wait, she was crazy anyway...
 
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