No start and no vacuum on start

[guylogan]

Today I double checked the choke closing by pulling the flame arrester off and checking that it was closed. I also put my hand over the carb throat and cranked it and got 10 inches of vacuum. I'm don't know if this is normal but eliminates my earlier theory that the manifold had a leak.

I also did another compression check and got 60 on all cylinders except 3 which was 40, also confirmed a spark at each plug. I still have to get into that timing possibility and plugged exhaust.

So I'm still stumped.

[Marian Claire]

What is the quality of the spark? Blue and jumps 1/2 inch or yellow and jumps 1/8 inch. Dan S/V Marian Claire

[guylogan]

Quality of the spark wow, I tested with a inline plug tester and the spark was defintely yellow but seemed robust. I'm more concerned with the decreasing compression readings, a coulple of months ago I had 50 dry and 85 wet. yesterday I tested wet and only got 60.

I don't want to give up yet, need to check that timing and pluged exhaust,
but maybe, just maybe it might be time to consider geting her rebuilt.

I hope not.

[Dave Neptune]

Checks and

guylogan, did you put the "rotor" back in. This just happened recently on another post.

Did you try to start on "motor crack" again?

I doubt the plugged exhaust as they will usually start and idle even when there is just no power available when throttled up

How did it run the last time it ran?

Dave Neptune

[guylogan]

The last time it ran everything was normal, that was about a month ago now.
I diden't know that the position of the throttle could effect a compression test. I'm sure it was closed when I did that test yesterday. maybe I should re-do it with it open.

I haven't tried the motor crack again. Also I have a vacuum gage that says it can also test fuel pump preasure. I guess you must just plug it in to the fuel line, run the pump and get a number. What number is good?

I will check the dist when I do the TDC timing thing, although I think it should be ok since I am getting a spark and don't think the dist has move. But you know what assume means.....

[Dave Neptune]

Compression check

guylogan, anything over 2 psi is fine for fuel.

When doing a compression test, first have the batteries fully charged, pull all four plugs, shut off water and open both the throttle and the choke all the way!
Do first test dry and then with a squirt of oil in the cylinders.

Double check the plug wires for correct firing order and be sure the rotor is in place before attempting to start after the compression check. Try a quick spritz of motor crack once your sure there is fuel in the carb.

Make sure the plugs are dry too.

If it starts it is going to spit a lot of smoke out the exhaust and may sputter a bit~don't worry about that if it runs. If it does run for a bit try to keep it running long enough to warm up then do another comp0ression check dry while warm too.

Keep an eye on the oil pressure to incase it is causing the OPSS to cut out and starve the carb.

Dave Neptune

[guylogan]

Thanks dave, I most likley won't get around to any more checking till after Thanksgiving. Travling to Kentucky and Florida for the holiday. So thanks for the input and I'll get back online when I get back.