vacuum issue

[Brent B3B]

been working on my HH for a year, I was pretty happy, got it running to the point I don't need the choke to start It.... until I wanted to start it up for my dad. it had sat for about 3 weeks prior and had a hard time starting. I used the choke and a plug (yellow in photo), I have on the vacuum line (in place of the vacuum wiper line)

popped off and then it started. first question, what the heck!? it is a 236, new valves, the vacuum is 20 at idle but the needle bounces. I thought I read something about a bouncing needle but I can't find it. could the two issues be associated?

 

[Don Coatney]

Sitting for 3 weeks the gasoline in your carburetor probably evaporated. Most likely it was a coincidence that the engine started when you removed the vacuum line. Suspect your fuel pump finally supplied gas to the carburetor about the same time you removed the line. Suggest you follow the procedure below when starting your engine after sitting for a long time.

 

 

Suggest when starting you spin your starter in short 5-6 second bursts. Then wait 15 or so seconds until you hit it again for another 5-6 seconds. Pump the gas pedal several times between the starter bursts. Continual cranking with the starter motor builds heat and the heat increases resistance making everything work harder and slower. I cringe when I hear people continue cranking the starter motor until it darn near quits. Give it a break and let it cool down.

[Brent B3B]

I have heard that about the starters overheating..... the weird part is, i have had the line removed and a plug in its place for about a year. I did not remove the plug, it physically popped off and the engine started.

wonder if i am looking at this as a vacuum issue..... could it be a compression issue?

[Reg Evans]

Don's method of starting works well but sometimes I still like to prime the carb with a small amount of gas or starting fluid.  If your air cleaner is on the carb just loosen up the wing nut on top and dribble some down the hole. No need to remove the air cleaner.

[John-T-53]

Sounds like your carb might be flooding the engine, given that you don't need any choke to start it. The vacuum plug could have let more fresh air in to "correct" the mixture.

Have you rebuilt the carb and checked all the settings?

When trying to start it, look down the carb....it is wet with gas? Use a flashlight and look to the bottom of the manifold with throttle wide open and look for puddling.

[Jeff Balazs]

If your vacuum reading is bouncing at idle then you have a bit of a problem. There are some very good tutorials online to help you understand what is happening.

My guess is a couple of sticking valves.....but without actually seeing the gauge I am just guessing.

 

Here is my take on a starting procedure. The first thing to verify is the quality of the spark you are getting. Take an old plug and open up the gap to at least twice the normal gap and use it as a tester to see what you get. You should see a nice blue spark. If it is a feeble yellow then the ignition system needs some attention before you go any further  Once you have verified that you have a good hot spark then try pumping the pedal 2 or 3 times with the hand throttle pulled out about 1/4 of the way. You may or may not need a bit of choke. It should fire up immediately,

 

Jeff

[Brent B3B]

guess I should clarify the needle bouncing.... it is bouncing back and forth between 19 and 20 at idle. at first I thought it was my gauge but I tried it on my fresh 218 and it is rock solid at 20...

if the bouncing indicates a sticking valve, is it possible moisture/ condensation is causing the sticking and back pressure would have popped the plug out?

 

I will defiantly be checking out the carb situation (no JT, it was not rebuilt or adjusted)  I have some other tests to do for fuel delivery (bubbles in the glass sediment bowl)

 

I started it once a week and it started great, without issues, even to the point I could start it with the hand crank. and after sitting he is being stubborn....

thanks for the help,