My Atomic 4 has fuel issue's?

[yeahjohn]

I picked up a 1980 Catalina 30 with atomic 4. Engine looks pretty good, had a recent rebuild but had not been ran for 3 years. I brought it back to life with marvel mystery oil, new spark plugs (old ones looked good but just for fun), new ignition coil (it had the original one on it), and new water separator. The engine will idle but only for about 5 minutes than die, if you nurse the throttle and listen to the engine it will idle longer. As soon as you go to increase throttle or put the engine in gear the engine dies. I feel that everything points to cleaning the carburetor, and the carb on a few occasions has dripped gas at flame arrestor. Am I on the right path or is there something I might be missing? Also, the choke has to be operated by hand at the carb, but it does open and close, I bought a few parts for the carb and the choke but before I pulled it apart I wanted to here your thoughts. Also the engine does not have a inline fuel filter just the large twist on separator. Thanks. John.

[sastanley]

Hi JOhn, welcome to the group.

We'll get you going. I am going to guess the carb is all varnished up. I had black tar like stuff come out of various orifrices on a carb that had sat for several years.

It sounds like the idle jet is letting some fuel in, but when it attempts to pull fuel thru the main jet (1,100 RPM or so), it won't, & dies. One thing you can try, but I suspect it will do no good is too flush some fuel out of the carb's drain plug on the aft end of the carb bowl..sometimes this will flush some debris out of the main jet, but likely won't help a varnish clog.

The choke cable on our Catalina 30's is a little longer than most, since our engines are in the middle of the boat. IS the cable attached to the carb at all? The A-4 usually needs full choke to start, but after 20-30 seconds should be done with the choke in a warm climate. A couple pics of the carb before removal, & we can probably help get the choke straightened out when you re-assemble. The outside sheath is clamped roughly 1.5 to 2" aft of the armeture, and the inside cable is clamped to the armeture..it is a little delicate, and sometimes the set/clamp screws strip or break.

I am sure I have a few pics in my album of that area for reference that you can get to by clicking on my user name.

There are lots of C-30 guys here, and your 1980 is one of the newer A-4's made.

One fun fact, when you pull the carb off, you'll be able to see a 6 digit number stamped in the block (mine is 041976) to indicate a block date of April 19, 1976.

As you've noticed, engine access is generally good for us..we have it a lot easier than most.

You will likely tear up a couple gaskets removing the carb, so I might start a list for Moyer Marine to save shipping/handling charges...First item on that list if you don't already have one is the Moyer Service Manual..second item may be the inline filter between fuel pump & carb, etc..etc..it adds up quick, especially on initial ownership..now I am lucky and just seem to be calling Ken in parts for a "spares & annual maintenance" purchases, like a few gaskets/impellers and stuff.

Out there in CA you might have some other sources for parts too..but of course us forum regulars always like to push the site sponsor's store when we can because we like to keep them in business.

[edwardc]

Hi John. Welcome to the forum. You've come to the right place for all things Atomic 4.

Your symptom of running for a few minutes, then dying sounds like you're running on the gas in the float bowl and it's not being refilled quick enough. This is reinforced by your description of being able to nurse the throttle to keep it running a little longer.

Two typical causes of this problem are either a stuck shut float valve or a malfunctioning fuel pump. Since you also describe a few occasions where gas drips from the carb, I'm going to go with the stuck float valve, as the dripping problem is usually caused by a stuck open float valve.

I suspect when you open your carb, you're going to find a lot of gelled crud in the float bowl interfering with the float action, and the rubber tip of the float valve needle deteriorated. Order a replacement needle and seat from Moyer, as well an new gaskets for the carb body and the manifold flange.

[sastanley]

Ed, Good suggestions. I didn't even think about a blocked needle, but it makes perfect sense given the duration of engine run time.

[yeahjohn]

Thanks for the fast reply! It seems I am going in the right direction then, I ordered a few new gaskets and a choke cable clamp and a choke spring and some other random items I though may be needed. I have a spare carb that is in good shape so I have and handful of parts from that backup. I will grab the serial number off the block as well. What is the best way to approach the carb cleaning? Are there easier methods for a quick clean? Or is a full break down required? Just unbolt it spray carb cleaner inside wipe it down and make sure everything is freed up? Thanks for the help.

[yeahjohn]

Will it be obvious how to clean the needle and if it needs replaced? or will it take a well trained eye. I have a spare needle and seat, from my other carb that look like they are clean and in good shape. One side question sastanley, my #1 spark plug hits my settee cover is this normal on the catalina 30? Is there a work around. Are my plug wires the wrong size?

[Marian Claire]

yeahjohn: I would suggest you disassemble the carb completely. They are fairly simple. I was intimidated the first time I cleaned my carb but you will be fine. Work over a pan to catch small parts. Look thru each piece before you shot it with carb cleaner. You can often see the crud and then see that it is cleared out after hitting it with the cleaner. Us safety glasses as the cleaner can shoot back on you. Small wire for the idle ports. Do you have the suggested factory setting for the idle jet and the main jet if yours is adjustable? Dan S/V Marian Claire

[roadnsky]

Will it be obvious how to clean the needle and if it needs replaced? or will it take a well trained eye.

If you really want some "confidence insurance", just download the carb video?
Great education for 12 bucks!

http://www.moyermarine.com/cgi-bin/shopper.cgi?search=action&category=CLIP&keywords=all&template=Templates/B000_storebuilder.html

[positron]

Just go ahead and order the carb rebuild kit- by the time you finish cleaning the carb thoroughly you have done most of the disassembly needed for a rebuild. The instructions are great and it is pretty straightforward, takes about 3 hours if you go really slow and careful. I found little sandy black chunks blocking most of the orifices. I replaced the old rubber fuel lines with new ethanol-friendly tubing, and also added the polishing filter for good measure to catch any lingering particles.

Take a couple of photos as you disassemble. Some parts like the throttle valve can be reassembled in several ways but only one is correct. It seems obvious when you are taking it apart, but after a couple of celebratory beers when you get it all apart, the last parts of reassembly can be tricky.

[yeahjohn]

Okay friends. Thanks for the support but disaster strikes (As always?)!!! First things first my engine was stamped 031778, so March 17, 1978. Pretty Cool. Now to the disaster... Check out the photo... strange, and I am not talking about the vice grips... I have a 1st gen carb!!!

So at some point the manifold was replaced, when replaced they used a old one? They went with the carb that was on it?

My back up carb is the 68 series, and it is in good shape but I am not sure if it is complete. So I need to order the flange adapter to fit my 68 series carb to the old manifold.

Also what are those vice grips doing? acting as the throttle cable clamp? Where can I order one?

And last the gas line from the fuel pump to the carb is copper and has a valve on it to drain gas? Shouldn't I replace that with hose and a filter?

When I replace fittings do they self seal? or do I need to use sealant of some kind? Thanks in advanced! Oh yes and I watched the mm carb video earlier today, and picked up all the parts and was ready to go until I realized my new issues.

[yeahjohn]

okay okay. This carb is so pieced together... is it the old style uper? With the new style bowl? Or not a zenith carb at all? The scavenge tube bolts onto the bottom of the bowl... Oh boy. Well a carb kit get me every part I need for my spare 68 series carb, I noticed some bolts and stuff missing, like the main jet bolt and then the bolts that hold the bowl on... Thanks.

[Marian Claire]

Looking at the pic I believe the scavenge tube actually goes to the carb throat, as it should, not the bowl. I am not a carb expert, but if you handed me this carb I would guess that it was a 4 bolt late model. The scavenge tube, fixed main jet and the flame arrestor shape suggest that.
Your manifold has a port for the scavenge tube so I see no reason why you would need the adapter.
The rebuild kits have all the parts that normally wear out. You can reuse the bolts that hold the half's together. Dan S/V Marian Claire

[sastanley]

John, Great pictures..it really helps to see what you are dealing with. That carb looks similar to mine.."Bendix" is a Zenith carb. You are on the right track..let's tackle this zoo of parts & P.O. (previous owner) monstrosities (sp??) one at a time.

choke & carb - Your choke cable appears intact, & you are missing the spring. However, depending on the position of the knob at the other end of the cable in that photo, you probably don't have enough travel in the cable, (unless it is already fully closed in that pic), so it might need adjustment. No worries there since you will have to disconnect it anyway when you remove the carb..which I highly suggest..there is enough external crud that who knows what is going on inside the carb. I'd remove it, crack it open, and clean. In addition to carb cleaner, strip the plastic off a twist tie because there are little tiny holes near the main carb throttle butterfly valve that don't usually clean up with carb cleaner. That carb video I am sure pointed that out. As Dan noted, your scavenge tube config is stock..it bolts into the bottom of the carb throat, just inside the choke butterfly...all good there.

Fuel line - I suspect that "tee" on the fuel line may have been for a fuel pressure gauge since there are threads on it, or some other filter/flush device..who knows? If you want to flush some fuel, you generally use one of the plugs in the float bowl (aft side of carb) to get the crud flushed out that may be lurking in the bottom of the carb or main jet. However, I don't think that is a fuel approved petcock, so I'd get rid of that whole rig. Screw on fittings are supposed to self-seal, they are NPT threads(tapered). I still like to use some Permatex (#2 or #3) on my fuel line threads, as you can't always get the threads as tight as you wish given the angles you may encounter when running fuel lines. I do not recommend teflon thread tape as pieces can break off and get stuck in carb jets. I would replace all hard lines with threaded barbs & A-1 (alcohol/ethanol OK) fuel hose, & put a "polishing" filter where that "tee" is between the pump & carb. We can deal with fun stuff like pressure gauges later.

Vice Grips - The vice grip looks like a clamp for the throttle cable..those brackets like to fail & I think they are mild steel..if you aren't real handy, Moyer has a nice stainless one in their catalog. You could fabricate one out of some angle stock.

Spark plug hitting settee..that should NOT be a problem on Atomic4 Catalina 30's..they did have that problem with the taller diesels installed later and built little boxes into the seat cushion as a workaround. My plug wire boot makes a 90 degree bend. What type of plugs are in the engine? Stock is Champion RJ8's..they are stubby lawnmower plugs..a P.O. installed long/hotter plug & funky wires could present a clearance problem, but I am running longer plugs than the RJ8's currently, and have never had a plug wire clearance problem.

Oh..what fun trying to figure out what P.O.'s were thinking!

If you want to see a great example, check out the Moyer panoramic engine..at least it shows how they are generally set up in modern 'stock form', without a bunch of P.O. modifications. Take special note of the fuel line/filter configuration since yours is highly modified already & also the spark plug height..The very first thing I bought from Moyer was spark plug wires, that look the same as the ones in the panoramic on the Moyer homepage. The only real thing I see different between your carb & the Moyer picture is the Moyer carb is the rare 5 bolt carb (a 5th screw in the front of the carb holding the two halves together), however, it does not have the 2nd tapered drain plug that yours, mine & most others have coming out of the bottom of the float bowl (although it could be hiding behind a fuel line.)

If I forgot anything, I'll edit my post. - Ok..couple small edits.

[Marian Claire]

One of the issues we run into with the A-4 is that often parts/engines have been mixed/modified etc. As far as carbs go it is my understanding that prier 1969 the A-4 came with the Zenith series 61 carb. It was cast iron, had an adjustable main jet, used 4 bolts to attach the half's, no scavenge tube and the flame arrestor was oriented vertically.
After 1969 Zenith bought Bendix so many of the series 68 had both the Bendix and the Zenith name on them. The 68 came with, aluminum construction, 4 bolts, fixed jet, the flame arrestor was oriented horizontally and the scavenge tube was standard equipment. Only the very last 68s had the 5 bolt set up.
Having said all this it is possible to have most any combination of these parts. You can add the adjustable jet to the late carb. With an adapter you can use the late flame arrestor to the early carb. I do not think you can mix early and late upper and lower half's. FWIW. Corrections please. Dan S/V Marian Claire

[ndutton]

yeahjohn,

How about a picture of the spare carb? I'm thinking you might be better off resurrecting that one instead.

I'm also thinking you might have a fuel delivery problem. That is, from the tank to the carb, up to and including the float valve. The 5 minute run and die symptom suggests that if there's fuel in the carb bowl she runs. Once that fuel is depleted it's not sufficiently replenished and the engine is starved. I say not sufficiently because I once forgot to turn on the fuel valve at startup. The engine ran for 1 - 2 minutes, not 5, on bowl fuel only. Your 5 minute run time implies you're getting a little fuel delivery, very little, too little. It can't keep up with consumption.

Just a guess.