Engine won't start

[MightyMike]

The screw you are adjusting is for the "idle air" so open is lean and closed is rich.

Were you careful with the float setting?

Dave Neptune

Dave, I did not change the float settings. I didn't have a screwdriver wide enough to remove the float valve seat and I did not want to burr it up. The valve itself appeared clean as a whistle.

[Dave Neptune]

Mike, both the idle screw and the adj main jet start at about 1 1/2 turns off of the seat is where to start.

The idle screw adjust air so out is lean and in is rich!

The adj main jet is out for rich and in for lean! The adj-jet was designed to "tweak" the mix for fine tuning. The jet size is just a bit bigger than the stock one so the needle will influence the fuel flow, however once you are about 2 1/2 turns out the needle is pretty much done with it's ability to add more fuel. It is a sensitive adjustment.

Did you check to see if the float was at the correct setting?

When you were messing with the rotor did you check the centrifugal advance for smooth operation? Very important.

Dave Neptune

[MightyMike]

Mike, both the idle screw and the adj main jet start at about 1 1/2 turns off of the seat is where to start.

The idle screw adjust air so out is lean and in is rich!

The adj main jet is out for rich and in for lean! The adj-jet was designed to "tweak" the mix for fine tuning. The jet size is just a bit bigger than the stock one so the needle will influence the fuel flow, however once you are about 2 1/2 turns out the needle is pretty much done with it's ability to add more fuel. It is a sensitive adjustment.

Did you check to see if the float was at the correct setting?

When you were messing with the rotor did you check the centrifugal advance for smooth operation? Very important.

Dave Neptune

Hi, Dave,
I am going back down to the boat and will try jet settings as you suggest. I had read somewhere that the main jet should be at 3 turns out.

I am unfamiliar with the centrifugal advance, but will do some more reading.

I will also look into the float settings. I seem to be at an impasse here and am thinking I should pull the carb again.

Appreciate all your help.

Mike

[Surcouf]

just to be 100% sure your carburetor / fuel supply is the issue, I would personally try to start again, confirm that the engine does not start, and try a second time with "start fluid spray", trying to maintain it running for 5-10 seconds. If the engine reacts positively to start pilot and does not without, you know it is very very unlikely that the issue lies with ignition, back-pressure, compression etc...

So many times I did some unnecessary "extra-work" by being non-systematic in my troubleshooting...

[Dave Neptune]

Mike, the rotor sits on top of the c-adv shaft. Just put the rotor on and give a twist, it should rotate just over 15* and spring back smoothly. If not some lubrication/cleaning may be in store for you. You can drop a bit of oil into the shaft housing when the rotor is removed, yep right down the hole. Won't lube the weights but can easily free up the shaft/counter-shaft assembly.

Not as tough as it sounds.

Dave Neptune

[roadnsky]

I had read somewhere that the main jet should be at 3 turns out.

Mike-
Actually, I believe it is 1.5 turns out. (See attached instructions)

I will also look into the float settings. I seem to be at an impasse here and am thinking I should pull the carb again.

Here are some float setting instructions I've kept in my 'word vault' (from Dave) ...

"When adjusting the float, err to the high side of the setting, which is a lower fuel level.

Hold the top half of the carb upside down with no gasket and the float installed, check the height with a scale (good ruler). The factory setting is 1 5/32" to the bottom of the float, which is on top and resting against the needle which is resting on the seat.
Two things of import here...
1-Be sure the bottom of the float is parallel with the body (this controls the closing position of the float accurately) of the carb, or as close as possible.
2-When tweaking the tabs use a pair of needle nose or duckbill pliers.
DO NOT PUSH, PULL OR BEND the tabs by holding the float itself. Only hold the brass tabs.
Now you can bend the larger portion that attaches to the float for the parallel adjustment and the little tab that rests on the seat for the height.
This can be a bit frustrating so go slow and easy. I suggest that if anything, you set the float a bit HIGH @ 1 3/16~1 5/32.
These adjustments are important to control the emulsion wells that mix air into the fuel to break it up! The factory adjustment specs are 1 5/32 +/_ 1/32" which is why you need it to be as parallel as possible. I run mine at 1 7/32 and like the way it performs."

[MightyMike]

Mike, the rotor sits on top of the c-adv shaft. Just put the rotor on and give a twist, it should rotate just over 15* and spring back smoothly. If not some lubrication/cleaning may be in store for you. You can drop a bit of oil into the shaft housing when the rotor is removed, yep right down the hole. Won't lube the weights but can easily free up the shaft/counter-shaft assembly.

Not as tough as it sounds.

Dave Neptune

thanks, Dave.
That does sound like something I can handle.

[MightyMike]

ordering rebuild kit

I have removed the carburetor again for another cleaning and a float adjustment based on what I have learned here.

I have spoken to the previous owner who tells me re did a full rebuild 7 or 8 years ago. I am thinking I will go with the more limited zenith kit since he has already changed out all the Jets etc. Based on this timeline, does anyone think I should do a full rebuild instead?

I have also mangled the scavange tube. I have ordered the replacement, but it is back ordered. I used a bit of jbweld to seal the fittings the last time, but I am thinking of replacing with caps temporarily while waiting for the back order.

I know they are 1/8 flair fittings, bit I don't know what the threaded side is. They seem larger than 1/8 inch.

Thanks

[Dave Neptune]

Mike, you can use either compression or flare fittings for 1/8 copper tubing. The port in the manifold and the carb are 1/8 NPT std fittings. Easy to fab on your own. The scavenge tube is a very important safety factor for an updraft marine carb!!!

Dave Neptune

[capnward]

A full rebuild of the carb, which is a replacement of the jets and other internal parts, is unnecessary as long as your existing parts are clean and installed correctly. But it won't hurt. With ethanol fuel the rubber tip of the float valve needle may degrade over time, in my opinion. The rebuild kit you get from Moyer has a small tapered wooden dowel which is used to dress the float valve seat. Should be no need to remove the seat.
Since you are taking the carb apart, I suggest you remove and inspect the tiny idle jet, although that is not causing your non-starting problem. File down a screwdriver so that it fits the slot in the jet snugly, and doesn't damage the threads in the carb. Once you have removed the jet, you can hold it up to the light and see any crud blocking it. It doesn't take much to mess up your idle. Then run a thin wire around in it to clear the crud. Spraying cleaner through it isn't enough. You wont see any blockage unless you remove it.
But I suspect your problem may be idle mixture adjustment. What you called the idle jet is actually the idle mixture adjustment needle valve. Page 4-3 of the Moyer manual shows this difference clearly. If you had it turned further out than 1 1/2 turns, it was adding too much air to the mixture, so it wouldn't start. Same effect as the choke not closing completely. Make sure you have a tight fit at the gasket where the carb joins the manifold. A new gasket helps with this.
Turn your adjustable main jet in all the way, then back it out 1 1/2 turns. This may clear any crud in it.
If you are one of us primitives with a mechanical fuel pump, you can use the hand bail to pressurize the fuel line all the way to the float valve before starting, and it will start sooner. If you have a fuel pressure gauge, you will see when the line has pressure. But you can feel it pressurize when the bail goes completely slack. You can hear the fuel filling the system as you pump it by hand. Then the sound goes away when it's full.
+1 on fixing the scavenge tube right away. You do not want it dripping into the bilge.
Keep up the good work. You are almost there. Let us know how it goes.

[MightyMike]

Got it started today

While waiting for the Zenith service kit to arrive from Moyer, I decided to do another cleaning attempt.

I did not notice the fixed part of the main jet the first time, but I removed it this time and clearly saw the blockage.

After replacing the carb, it fired right up, just as it always has.

I still need to set the idle and main jet correctly, it it doesn't sound too bad as is.

I have two other issues to resolve.

Scavange tube
The drain plug at the bottom of the carburetor.

I am still back ordered on the scavenge tube and the old tube no longer seals at either fitting. JBWELD seemed to work the first time, but not sure if it will hold up to extended use.

Does anyone have thoughts on an alternative?

On the drain plug, the threads are pretty much gone on the carb side. Short of retapping the fitting, can anyone recommend some magic goop that will get me through the season?

I tried some pipe drop and it was not leaking tonight, but I can hand spin it, so I am not feeling very comfortable about that solution.

Again thanks to everyone for their help. I was quite surprised I didn't end up with a yard bill for this.

[Peter]

Did you see this from Dave a few posts back?

Mike, you can use either compression or flare fittings for 1/8 copper tubing. The port in the manifold and the carb are 1/8 NPT std fittings. Easy to fab on your own. The scavenge tube is a very important safety factor for an updraft marine carb!!!

Dave Neptune

Goop on drain - there is no way I would go with goop there. Retap sounds much safer or maybe scrounge up another carb body?

Peter

[idreamOfSailing]

Resetting of Number 1 cylinder

I noticed the cylinders have been wired in reverse from the distributor, meaning the 1-position on the distributor goes to number-4 cylinder, 2-position to number-3, 3-position to number-1 and finally 4-position to number-2 cylinder, so in terms of firing order, correctly I think. If however I were to rewire according to the book, would I simply find the top of true cylinder-1 (first from the flywheel) and connect to distributor position-1 and then follow the usual firing pattern for the other cylinders, or is there something else I should know? My thinking is, since the distributor is firing in correct order there's nothing that needs to change there. Thanks.

[ndutton]

Dream, I didn't see any mention of rotor position in your post. The distributor post that should be connected to cylinder #1 at TDC is the one the rotor is pointing to, then the remainder are connected following the firing order.

[idreamOfSailing]

Hi Dutton. Thanks for yuor response. I think I did mention it though. I said the position-1 on the distributor, which I take it you're calling position-1 on the rotor, currently goes to the number-4 cylinder. So, if I understand, all I need do is move that wire to the number-1 cylinder at TDC and then move all the other wires to their correct cylinder without changing any of the positions on the rotor. I'd have rotor-1 goes to cylinder-1, rotor-2 to cylinder-2, rotor-3 to cylinder-4 and rotor-4 to cylinder-3. Do I understand correctly?