DMSA on a 1608

[JTBernhardt]

I put a single plane manifold and a 34 DMSA on my '72 tonight. It started up fine, but after it warmed up the idle stayed at 3000 RPM's. The choke was fully disengaged, but the RPM's wouldn't come down. What would cause such high RPM's? I have a feeling the carb needs to be tinkered with, but it'd be nice to know exactly what type of tinkering it needs.

Thanks!

[nibbes123]

Try to to set the fast idle down a bit .

[fiat218]

linkage not catching any where?

[georgeramos]

id love to hear about the difference with the new manifold/carb once you resolve your idle issue. I know its a worthwhile upgrade but am interested to hear firsthand experience with it. performance/fuel economy stufflike that...

Good luck and thanks

George

[Dougieb]

Hi,
I put a DMSA on my '72 Spider also. First, I set the carb back to the factory setting. I used Artigue's guide for that.
Then I used his steps to dial in the carb for my engine.
(as I remember it)
1: set carb to factory setting and start engine.
2: use idle adjust to get car idling about 900 rpms.
3: adjust mixture screw to optimum setting.
4: let car warm up completely.
5: repeat steps 2 and 3

I ended up dialing down the idle adjust a lot before I could get it in the correct range for the mixture screw to be effective.
I think maybe that is because this carb has such a larger primary diaphram than the original DHSA for our cars.
But if you follow the procedure in as described by Artigue, you should be able to get there.

My car runs great with the "new" DMSA. I do not have any milage info as I am currently working on exhaust, interior, and heater issues.
But that is another story.

Let me know if you need more info on setting the carb back to factory settings or the exact procedure i used. I can send you a copy of it tomorrow.

Good luck,
Dougieb

[JTBernhardt]

The problem turned to be the throttle linkage getting stuck on the choke, which caused the car to idle unusually high. To fix this I ended up shortening the spring and putting a small shim on the throttle linkage.

I then had another problem; the car wouldn't run anymore. I could get it to start but when I hit the throttle the carb hissed and shot flames out the top. I eventually narrowed this down to timing. My old carb (DHSA) wouldn't idle for me, and I had some help from someone to get it to idle (However poorly). I didn't know, but they had advanced the timing, which caused problems for the new carb that had been rebuilt and set to factory settings. I borrowed a timing gun from a friend, timed the car, adjusted the idle and mixture, and now it idles perfectly at 900 RPM's.

The first time I drove the car there was a massive increase in torque. The car revved to 6.5k RPM's with no problem at all. I can't say exactly how much the fuel economy has improved, but it seemed to improve as I had driving the car down a super winding mountain road at high RPM's, and it didn't drop the gas gauge much. The only complaint I have with the DMSA and 1800 intake is that it seems to have less high end torque. I think perhaps it's a matter of fuel/air adjustment, but for now, it works.

The DMSA might be a little hard to find, and expensive when you do find one, but they're worth it if you're planning on upgrading an early spider. You don't have much fuss with throttle linkages, and very little has to be modified to make it work.

All in all this has been the best upgrade I've done to my car since the day I saved it from rotting in a field. It's quite nice to not worry about dieing at a stop light, or leaving the manual choke slightly on in the even of traffic.

[nibbes123]

Glad to hear you got the car running great, enjoy the the new set up.
Nick

[georgeramos]

Thank you for the info. I am currently working on rebuilding my DHSA2 until funds allow the purchase of the single plane manifold/new carb.

George