cdrad51

I really have no better way to name the subject of this thread. I was having some troubles with my newly dropped in RB size SP engine, and I was atributing them to the carb, maybe a vacuum leak somewhere. Rough idle, hesitation when accelerating - to the point of stalling some times - backfiring when shutting engine off. Well, finally decided to check the obvious, so bought a timing light. The timing was quite retarded!! upon advancing it the engine started singing a totally different song. After adjustment, went for a short ride. Hesitation is totally gone! engine feels smoother, more power, and at the end of the run, when shutting the engine off, no backfire!

DUH!

85rotarypower

The backfire was from unburnt or partially burnt fuel in the system. The timing was just so far off that the spark was so late that it didn't ignite all the air/fuel mix, dumping it into the exhaust. This is also the cause of your hesitation since it was almost flooding the engine out, even at normal fuel mixture.

9d7gst

Your not alone brother. I have been battling an idle problem. Done every thing to the carb, nothing to the timing. Havent even thought about checking it. Thank you for turning the light on in my head.

cdrad51

Hey no prob. Let me know how it went.

85rotarypower

To tell you the truth, that was the last thing I thought of on my car too. I didn't really have any idle problems, but I just decided to check the timing just for the hell of it bacause it just didn't seem to run properly when cruising or decellerating. The only difference is that my timing was way advanced (probably 20 degrees or more, but not sure). This MIGHT be why the car was sold in the first place though. The distributor was VERY hard to turn and it seems to be off by about a tooth or more on the gear. Its not perfect, but very close. But I can't adjust it any more. Its at the limits of the slot, and I can't take it out because its stuck in the front plate. I had to use a hammer and flat blade screwdriver to turn it.