No start and no vacuum on start

[guylogan]

Need advise on getting her started. I'v done all the troubleshooting outlined in the manuals, got spark at the plugs and coil, compression not great (50's dry 85 wet). no fuel in cylinders. So I bought a new carb from Don and changed fuel tank to a portable one with fresh gas. NO JOY...Today I put a vacuum gage on the scavanger tube connection on the manifold, and got zero inches while cranking her over. So the question is how much vacuum should I have when I crank it. And if thats the problem how likley is a vacuum leak from with-in the maniold.

I don't understand how the manifold works ( I know it has intake exhaust and cooling) but what I mean is with 6 holes between the head and manifold. Which ones are which and where could a vacumme leak be. I tried ether around the edge of the manifold but it diden't help. Also there's no water in the oil or in the cylinders.

Oh buy the way the boats a Columbia 36 in San Diego Bay.

[Marian Claire]

Welcome to the forum. The holes are E-[I-I]-E-E-[I-I]-E. E = exhaust I = intake. The intakes are joined together, siamesed, so you have 6 holes. All of that is surrounded by a water jacket. Possible stuck E valves?? Dan S/V Marian Claire

[Mo]

I agree Dan. I would call MMI and order the head gaskets. Then pull the head, clean, and reseat the valves. Sometimes the fooling around trying to free up valves with oil can be a nuisance. I pulled the head off mine in 2007 and did them... haven't had a problem with valves since. Total time was a couple of hours at the most. Sometimes it better to bite the bullet.

[Dave Neptune]

Depends

guylogan, not seeing a vacuum reading at cranking speed is not a real issue! You should see the gage moving up a bit but it will depend on the carb and choke setting.

Is the choke fully closed and functioning? Take a good look! If the choke is not closing completely you will see little vac at cranking speeds!

Your compression could be off due to sticky rings as the oily compression numbers indicate. I'd try a bit of "motor crack" to start and see if she runs a bit that way. Just a quick "spritz" on the flame arrestor will be PLENTY!

If it starts and blows a bit of smoke out don't worry for a few minutes, it's the oil. After she runs for a few minutes do another compression check with all the plugs out and the throttle at wide open~then get back. Do two checks one dry and one with a spray of oil in the cylinders.

Dave Neptune

[Mo]

Good assessment Dave. Should have thought of that, you might be bang on with that one.

[JOHN COOKSON]

This sounds kind of silly but I haven't seen it mentioned yet so here goes:
Is there any gas in the carburetor?

TRUE GRIT

[guylogan]

Thanks guys for the help. What does clean up the valves mean? The choke was closed when I was cranking and there was fuel in te bottom of the bowl.
I had tried ether but it dident help. Thanks again, so its off with the head to fix stuck exhaust valves.

[Dave Neptune]

Whoa

guylogan, if you have 50 in the cylinders I doubt you have any valve seating problems. If you have spark and tried "motor crack" it should at least try to start.

How do the plugs look?

Are you sure the choke is fully closing?

Are you sure the plug wires and the timing are OK?

Dave Neptune

[Marian Claire]

guylogan: Whoa is right. My comment about exhaust valves was more a question to the forum than a recommendation for action. Most of these folks have a great deal more wrench turning knowledge than I ever will.
What type of fuel pump do you have? When you say the choke was closed did you visually verify that by removing the spark arrestor and looking?
Dan S/V Marian Claire

[guylogan]

There is one thing I thought about and that is a plugged exhaust, I din't know how to test for it other that pulling the exhaust from the back of the manifold. Or I could open the cap on the front of the manifold and prob it.

As for the timeing I havent moved the distributer, did take the cap off and ran a business car thru the points, but again all the plugs are fireing, could I have broken and advance srping?

The fuel pump seems to be working fine, I have shorted across the oil presure swith and ran about a half a pint thru when I was draining the float bowl when I switched to the temp fuel tank.

Mabey the stuck exhaust valve is the problem, so before I pull the head i'll go down and try to get each cylinder on an exhaust stroke so the valve should be open and soak it in MMO and mabey even a squirt of rust buster.

[ndutton]

When the guys ask about the choke closing they don't mean pulling on the cable and calling it good. They mean removing the intake air horn and visually inspecting the choke closure up close and personal.

[Mo]

Dave Neptune has very good points indeed when he mentioned the rings.

Just a few things Ive seen with A4 valve issues. Compression needs to be checked with a gauge because valve problems can be missed or misdiagnosed without a proper test. The thumb method (compression blowing thumb off spark plug hole) is a good ball park but is not a good indicator of exactly what is going on there.

-sometimes they are so stuck there is little or no compression.
-sometimes the thumb test will work, the engine will start, will idle good, will throttle up in neutral.... however may stall or have no power when in gear.
-individual cylinder compression numbers can help pinpoint the trouble area and cause sometimes.

Compression test with a gauge always a good thing when in doubt of valve performance.

[roadnsky]

When the guys ask about the choke closing they don't mean pulling on the cable and calling it good. They mean removing the intake air horn and visually inspecting the choke closure up close and personal.

Like this...

First pic is CLOSED.

[Dave Neptune]

Points

guylogan, you drug a credit card through the points, not necessarily a good thing. I have seen a tiny spec of paper get caught and reek havoc. If you are going to check them or remove oil and or moisture from points keep that in mind. I recommend you get a "point file" or a good abrasive style finger nail file for doing the points. The abrasion will remove deposits and clean the surface for good contact.

Check the spark again and do look into the choke.

Doubt you broke a spring in the adv mechanism.

If you can use a spray on the valve stems try a bit of carb or brake cleaner, as these will actually break down the deposit that cause the sticking. It doesn't take a lot of it if you are careful. And do change the oil after you get it started the cleaners are not good for the oil.

Dave Neptune

[sastanley]

guylogan,

As we've been discussing, the engine only needs three things to run: compression, spark & fuel. It sounds like you have all three. Fuel in the bottom of the carb indicates you have fuel. You need a fully closed choke butterfly as Jerry posted so the fuel will suck up the manifold and start the engine.

Since we seem to have eliminated most other issues, I am leaning towards a timing problem. Any more history on that? Were you the last one to adjust it? Do you have the access to observe the flywheel pin and get it to TDC & reset the distributor timing? I would also clean out the points with an emory board as Dave suggested. With the engine at #1 cylinder TDC (AND on the compression stroke), if you remove the cap, the rotor should be pointing at the number #1 wire. Can we confirm this? Sometimes a little twist on the distributor one way or the other while cranking will suddenly solve a start problem that had the timing just a few degrees out.