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View Full Version : Start up made easier, tips?


hkallestad
04-19-2010, 04:50 PM
I always have prime my carb on my 351 indmar before I start it cold, I also have to give it a bit of trottle to get it started. I now have electric choke set at the normal position. Would the engine start easier/without trottle if I adjust it to run richer at idle? Also when the engine is warm I have to give it a little bit of trottle to start it, it idles fine at 600-800 rpm. Any tips to get the engine to start without giving it trottle? Starter seem to run fine by the way.

thatsmrmastercraft
04-19-2010, 05:02 PM
When its cold, you will always have to give it one or two strokes of the throttle to supply it the fuel to start. If your choke is set properly, you should get sufficient RPM from the fast idle to run at while warming up with the throttle in neutral. As the RPM increases and the choke opens up, you should goose the throttle to allow the fast idle cam to reposition for a reduced RPM. If your carb doesn't have a fast idle cam, a little extra throttle until the engine is warmed up is normal.

Make sure you are getting power to your electric choke to assist it in opening. Choke springs need periodic replacement as the bi-metalic spring inside comes out of calibration after a number of years of use and doesn't open at the correct rate.

hkallestad
04-19-2010, 05:36 PM
Thanks, just bought the carb from national carbs, electrical choke works fine. I had the same startup "issues" with the old carb as well.

JimN
04-19-2010, 06:14 PM
If the motor hasn't run in more than a few days, you'll need to get some gas into the intake and cylinders, so pumping it once or twice is pretty normal with a carb. Whatever was in the cylinders and intake manifold is gone, so it needs a boost, initially. I wouldn't set the idle mixture rich- if you do that, it will run like crap once it warms up and the choke opens.

JUST-IN-TIME
04-27-2010, 02:36 AM
a good set up carb will start on one pump and forward a little on throttle

hz900
04-27-2010, 02:40 PM
Thanks, just bought the carb from national carbs, electrical choke works fine. I had the same startup "issues" with the old carb as well.

Wow, got the same exact thing from mine I just bought from them, and had the same problem with my old one. Once I get it started it runs/idles fine, alot better than the old carb, but still have to pump the throttle to get it to catch.

I have read that this could also be a problem with the fuel pump letting the fuel leak back, so it takes a bit to get it to prime again. I have not verified if this is even possible, maybe someone with more experience will chime in.

thatsmrmastercraft
04-27-2010, 02:54 PM
Fuel pressure leak down is only a function on fuel injected engines. With a carbed engine, the source for fuel at start-up is supplied from the primary bowl of the carb. When you give the throttle a half stroke prior to start up, it causes the accelerator pump to spray gas into the throat of the carb.

People have been driving injected cars long enough that they have forgotten the days of having to pump the gas pedal once prior to starting to supply fuel and to set the choke.

hkallestad
04-27-2010, 03:50 PM
a good set up carb will start on one pump and forward a little on throttle

That's exactly what I do and it starts fine, all normal then;-)