Excess Fuel?

[edwardc]

Marvel Mystery Oil (MMO) is your friend.

Put a tablespoon or two into each of the cylinders via the spark plug holes. Turn the engine over by hand to distribute the oil and let it sit for a day. Repeat. After a couple of days, try the compression check again. The valves will eventually loosen, but it may take time.

Once running, add a pint of MMO to the oil to get at the lower end, and some in the gas to get at the upper end. You may get some smoke, and the plugs may run a little dirtier, but it will clear up most stuck valve problems. After one tank of gas with MMO, you should probably return to straight gas, but there's no harm in running with the MMO in the oil all the time..

[JOHN COOKSON]

Maybe you could use a trigger type oil can to direct the MMO in the direction of the valves. I've never tried this but it sounds like it should work.
After the MMO treatment, before doing a compression check, you can get rid of a lot of the excess MMO by placing a rag over the top of the engine and then turning the engine with the starter.

TRUE GRIT

[sandiegomike]

Great!

Thanks Guys, BajahahaJim and I will give it a shot. We will keep you posted. I'll head to the harbor this Saturday.

[sandiegomike]

Black gunk in carb.

So BajaHahaJim and I pretty much got the valves unstuck in 2,3 and 4. Is it possible when both valves are stuck open in one cylinder that mystery oil can get pumed back into the carb? This is really thick black gunk and it appears to be comming through the little copper tube connected to the manifold. The other end is connected to the base of the carb close to the spark arrestor. We believe some is coming down through the carb where it is connected to the manifold also, but not sure. I am thinking it is MMO and once getting fired in the cylinder turns thick black.

We think this clogs everything up and causes fuel to be spitting up through the spark arrestor? Does that sound possible?

By the way, we removed the head to get the valves unstuck.

[JOHN COOKSON]

S. Is it possible when both valves are stuck open in one cylinder that mystery oil can get pumed back into the carb? This is really thick black gunk and it appears to be comming through the little copper tube connected to the manifold. The other end is connected to the base of the carb close to the spark arrestor. We believe some is coming down through the carb where it is connected to the manifold also, but not sure. I am thinking it is MMO and once getting fired in the cylinder turns thick black.

We think this clogs everything up and causes fuel to be spitting up through the spark arrestor? Does that sound possible?
.

You're close here. It's not cause it's effect. The idea behind the little copper tube carb -> manifold is that the vacuum in the manifold will aspirate any fuel in the throat of the carb into the manifold so it doesn't accumulate in the carb and over flow. If the tube is blocked at the manifold or carb this won't happen. The tube is not really part of the carburetor function. The excess fuel is coming from the carb itself, probably because the inlet needle jet is clogged up and not sealing well.

TRUE GRIT

[sandiegomike]

Black Gunk, thanks for the response

Thanks for the guidance on the copper tube. I will check out the fitting going into the manifold on Saturday. Will let you know how it goes. That is probably the reason the gas backs up and shoots out of the spark arrestor. The copper tube and the harden pool of gunk at the entrance to the tube in the carb is part of the problem. I do not remember seeing a bunch of gunk when we had the manifold off though.

[JOHN COOKSON]

Ok
Question: Is there something we can do to polish the valve stems and valve guides so they don't stick?
Wisdom and guidance appreciated!

Now that you have the valves freed up add MMO to the fuel. The standard dose is 4 ounces of MMO to 10 gallons of fuel. You can double the dose or even increase it more. The downside of this is it will tend to foul the spark plugs a bit.

TRUE GRIT

[sandiegomike]

Pics of the black gunk

Here are a few pictures of the black gunk I spoke about. This has happened twice in the last month while working on the engine. This is what I believe is burnt Mystery Oil coming back through the two stuck open valves. I believe it is coming down through the manifold and up through the copper aspirator tube then hardening. These pictures show the first time this happened. The second time it was much worse, I believe because I had squirted a lot of MMO under the stuck valves. As you can see, this gunk clogs everything.

[Dave Neptune]

sandiegomike, I have been looking over this thread and two things come to mind. First are you sure the plugs wires are in the correct order~this could cause the puffing through the arrestor.

Number two is from the KRAP around and leaking through the scavenge assembly I'll bet you have a cracked manifold or a water breach to it. The water would also explain the valves sticking.

Dave Neptune

[zesterjester]

Hi, do you have a fibreglass fuel tank? Sadly, I bet you do, and that black gunk is styrene and etc getting leached out of the tank by methanol. The only cure is a new tank, it seems. You could also try running methanol free gas, obtained from some understanding airport. Make sure you tell them you own a boat, it is illegal to use pure gasoline in a car and they won't sell to you if they think that is what it is for.

edit, this is well known to cause sticking valves http://www.boatus.com/seaworthy/fueltest.asp

[sandiegomike]

Black gunk in carb.

Thanks guys! Interesting comments. Well I have removed the valves and cleaned them. I will be reinstalling soon. Several of them were pretty crusty.

I have one of the red plastic portable fuel tanks. I don't see anything but clean gas inside. (new gas at that) I will be adding some MMO prior to starting and will pump enough into a spare tank to make sure I have the mixture to the carb.

Scavage tube is clear and I don't visually see any cracks in the manifold and no water coming out anywhere. Probably won't do a die penetrate test until after another run through.

I did order some carb parts from Moyer. The float valve needle seems to stick in the open position keeping the float from lifting and shutting off the flow. I attempted to clean, but it continues, so I decided to take the guess work out of it.

BTW, yes the plug wires are in the correct order. BajahahaJim makes sure of that!

[The Garbone]

My marina sell Ethanol free fuel, $3.65 a gallon. The WaWa gas station a block from the house has it for $2.80 last time I checked. This is Florida, can you get it in Cali?

If my motor sits for more than a month I bypass the cutoff and listen for the fuel pump to shut down, usually take 10 second. Put ever thing normal and Motor fires almost instantly. If I do not prime it it takes 15 seconds or so to kick over.

[sandiegomike]

Ethanol free - Gary

Hi Gary, not sure if we have ethanol free. I usually just take my 6 gallon red portable tank to buy gas at the local gas station. Can have up to 10% mixed in.

[sandiegomike]

Float Valve Needle - cockeyed

Seems the float valve needle was getting stuck as it came out too far and would not go back into the seat when the bowl filled with fuel. This, I believe, was the source of the excess fuel. It was cockeyed and on an angle. I adjusted the "tab" between the two hinge points where the pin holds the float to the carb housing. The "tab" now rests against the valve seat stopping the float from falling too low. This now keeps the float valve needle from coming out too far. Wish I would have taken a picture to show the issue. I have posted pics showing post adjustment. Kind of difficult to see.

Headed to the harbor in the next few days and will post the results.

Sorry, pics should be rotated right.

[Dave Neptune]

Mike, be absolutely sure the floats sit parallel with the carb body when inverted to check the clearance setting~~very important.

There are really two adjustments on setting the floats.
First maintain the parallelism between the body and float.
Second is the clearance.

Tweaking one will alter the other. Sit down with a couple of needle noose pliers and be patient. The results will be a good running carb that supplies a good mixture that is very well mixed when entering the manifold for better performance and "clean running".

Dave Neptune