|Throw Away That - P-60 (M-60) Zenith ...
|Posted on Thursday, July 07, 2005 - 11:02 am: ||
After extensive research and comparison between my (35hp) P-60 (M-60) Palmer Marine Engine and the Universal Atomic Four (35hp) - Gasoline Marine Engine, I decided that the cast iron body Zenith 61 Series Carb #10734 which came stock with the P-60 Palmer could perhaps be interchanged with the Zenith 68 Series Carb #13355K with respect to manifold, linkage and performance.
As all P-60 (M-60) Palmer Marine Engine owners know - The 61 Series Zenith is no longer available or just hard to find, the rebuild kits are hard to find too. I think I bought the last one in 1992 (joke). I rebuilt the original carb that came with the engine a 1/2 a dozen times over the course of 12 years, then in 1992, I purchased a new one, I have rebuilt that one too about 3 times. I believe everyone that owns a P-60 or M-60 Palmer Marine Engine, hates and knows the inevitable characteristics of the cast iron bodied 61 Series Zenith Carb and would love to just toss it overboard. Upon searching for a new source for the 61 Series Carb, I found a cross-reference web-site for Zenith rebuild kits and discontinued - superceded carburetors. I noticed that both the 61 & 68 Series carb used the same rebuild kit and that both had been used on Universal Atomic Four Engines.
I reviewed and compared the engine specifications and hp performance curve of the Universal Atomic Four with the P-60 Palmer Marine Engine extensively with conclusion that the 61 & 68 Zenith could be interchangeable. Very close power band torque performance curve between the two engines.
Moyer Marine sells an “ALUMINUM BODIED” 68 Series Zenith Carburetor with adapter kits that transition between the 61 & 68 carburetors.
The difference between the 61 & 68 Series Carbs are:
The 61 Series carb has an adjustable main jet – 68 Series has a fixed main jet (the 61 Series ran a little rich even jetted in considerably, they improved and incorporated a fixed jet for the 68 Series Carb).
The 61 Series carb has a built-in scavenger tube – 68 Series requires an external scavenger tube that incorporates an adapter plate between the intake manifold and the carb.
The 61 Series carb has a smaller diameter intake orifice than the 68 Series (an adapter coupler ring is available to accommodate the spark arrestor used on the 61 Series.
On my vessel "34ft Columbia Sloop, Mark II, the Palmer Engine is mounted with a slightly inclined slope to the rear of the engine, thus incorporating a wedge shaped adapter plate between the manifold and the carburetor (about 1/2" thick graduated to 3/8" thick iron plate) which I removed. The 1/2" thick aluminum adapter plate used for the scavenger tube that comes with the adapter kit fit well. The performance of the carburetor was not impeded. The carb bolted up nicely and accommodated the stock fuel line, choke and throttle linkage, the spark arrester ring adapter also fit with no problems. My engine runs great. The new 68 Series Zenith Carb with the scavenger tube adapter kit, and the spark arrester adapter coupler cost (with tax) $248.00 plus taxes/shipping & handling (optional).
Look-up Moyer Marine on the web-site, they have photos and pricing for this conversion.
No more cast iron carb problems.
Oh a tip on the Marvel Mystery Oil as a fuel additive (4oz to 10 gallons of gas). I always added Marvel Mystery Oil to the crankcase prior to draining the oil for an oil change but never added to the fuel for lubricant. Tip from Moyer Marine, says it helps prolong carburetor & internal engine life. I started using it.
Post Number: 1
|Posted on Sunday, June 29, 2008 - 08:51 pm: ||
I found a running Atomic 4 and had it installed in my boat, a 1975 Newport 28, replacing one that had long ago given up the ghost. It was running well for about two to three hours over two separate day trips, pushing us along at a good clip (5-6 knots). Suddenly, one day in late October, it filled the cabin with blue smoke. I turned it off and was able to return to my slip under sail (...and that's another story!). Since then it has not run; until Saturday, it wouldn't even start.
With the help of friends, I replaced the coil, determined the engine was getting spark, and discovered that I was not able to get enough choke to start it. I adjusted the choke, and in minutes, the A-Bomb was running good as ever. However, when put into forward gear, the engine suddenly slowed down considerably. If I stepped on the gas, it stalled. If I kept the gas at about a third full, the engine performed reliably, but only pushed the boat 2-3 knots. In reverse, the engine seemed to perform much better.
I am wondering if this might be due to the propeller being fouled or, as my friend suggests, that a carburetor adjustment will cure it.
|Posted on Friday, July 04, 2008 - 03:19 am: ||
I have the same problem with water getting in the oil. Expensive process just diagnosing the problem.
Richard A. Day Jr.
Post Number: 627
|Posted on Friday, July 04, 2008 - 06:36 pm: ||
They made a bronze Zenith 61 serues carburetor but not many are still around. Don't think your problems will go away with an aluminum carburetor. Ethanol collects water and the float bowl becomes a small battery which messes up everything. I suggest you put a drain cock on the bowl drain so you can positivly drain the bowl when shutting down for a few days or more. Don't be surprised if water builds up in the fuel tank and fuel lines.
Ethanol may be a great boondogle for investors hoping to make a fast buck but it is going to quickly cause a lot of problems which could have been avoided by thinking through big investments in ethanol production without thinking through what alcohol and water due to engines etc. My thought for the day.
Post Number: 6
|Posted on Thursday, July 17, 2008 - 08:46 am: ||
I have a zenith updraft brass carb and a cast iron one was used on a streight 8 flat head chrysler, has a petcock drain in float bowl and plug in upturn of intake, clamp on spark arrestor is broken if interested
call 718-448-5356 thanks Ed
Post Number: 7
|Posted on Thursday, July 17, 2008 - 08:59 am: ||
another picture of brass carb, last one was of bottom, didnt know how to remove it,this is a better view Ed 718 448 5356