Fresh rebuild/parts. Need first start procedure help

[frodrummer]

Just completed my first full 2pg rebuild on my 81 Marathon. Aside from the normal parts that come with a full rebuild kit, I also purchased a new carb, fuel pump, regulator, as well as the parts for the HEI upgrade. I am in the middle of prepping the engine bay for paint, then everything is going back in.

Few questions....

1. Is there anything I need to do (mostly fuel-wise) before the dreaded first crank?

2. It has the tank behind the seat, so its siphon fed. Just wondering if there is a priming procedure that I need to perform? I oiled everything pretty well during the rebuild (crank, cylinder, piston, etc) so it won't be starved for oil for at least a few cranks. However, I don't want to crank it over and over, only to find that I missed something simple. I do plan on mixing the first tank 50:1 as I oiled everything pretty well, however, I have seen people suggesting 40:1. Not sure which is better in this case.

3. Do I need to do anything special to a brand new carb? I am under the assumption that they tipically just need a general tuning out of the box.

4. Am I gapping the plug at 30, or is less gap better?


If it turns over, but doesn't fire, I just want to eliminate the possibility of it being a fuel issue. I can chase down an electrical issue fairly easily at that point. Any input would be appreciated.

[kyerik]

First tank should probably be mixed 40:1. If it was mine, I'd also dribble a little 2 cycle oil down the spark plug hole and crank it a bit to make certain the rings are well lubed before I installed the spark plug. Cranking it without the plug for awhile will help the fuel pump prime without draining the battery and will allow you to check for a consistent strong spark.

You should remove the bowl of the new carb and verify that the float is set correctly (float should be parallel to the bowl mounting surface when the carb is help upside down)

.030 will be fine for a plug gap, if you used an HEI coil, you could likely go 0.050. I think that HEI vehicles run a gap around 0.060

[frodrummer]

Originally Posted by kyerik

First tank should probably be mixed 40:1. If it was mine, I'd also dribble a little 2 cycle oil down the spark plug hole and crank it a bit to make certain the rings are well lubed before I installed the spark plug. Cranking it without the plug for awhile will help the fuel pump prime without draining the battery and will allow you to check for a consistent strong spark.

You should remove the bowl of the new carb and verify that the float is set correctly (float should be parallel to the bowl mounting surface when the carb is help upside down)

.030 will be fine for a plug gap, if you used an HEI coil, you could likely go 0.050. I think that HEI vehicles run a gap around 0.060

Thanks for the info kyerik. For clarification, I am assuming the absence of the spark plug while cranking will eliminate the "compression" within the chamber, making it easier for the starter to turn the motor - thus easing the strain on the battery? Or am I not even close?

[kyerik]

Exactly- the engine will spin more easily without a spark plug installed