How old is your Atomic 4 engine? Poll by decade.

[ILikeRust]

Here is what I have found on the web about the serial number:

Pre 1969: serial number is stamped on right, forward side of block above starter motor.

Post 1968: serial number is stamped on block above flywheel housing, and on an id tag glued to top of manifold.

Post 1977: serial number is stamped on block above flywheel housing, on an id tag glued to top of manifold, and on an id tag glued to front of the flywheel housing cover.

I know I had seen a page with more detail on dating your A4, but now I can't find it. Some of the links I had bookmarked less than a year ago are now dead. I plan on seeking out all the info I can find and saving it in case those sites vanish too.

[Loki9]

I don't know how old it is.

My s/n is 195476.

Block casting #s are 050 775 A and 295 369.

Can someone decode those?

[Laker]

Loki ,

Your block was cast on May 7 , 1975.

MM DD YR ; 05/07/75

(Decoding thanks to Edward c.)

[JOHN COOKSON]

New style serial # 204047 in a 1980 boat.
Where do I find the block casting date numbers?

TRUE GRIT

[edwardc]

My Moyer-rebuilt engine used a block with an 8/22/66 stamp, with an SN of 79034 . This is an early model block, but assembled with all late-model parts for all the other castings.

My original engine was a late-model. The block was stamped 051376 (May 13, 1976), with an SN of 197869. This date makes sense, as the boat, a Pearson 323, was built in December of 1976.

[tartansailboat]

new thread, carb mixture setting

Sorry if this message is hooked onto an existing thread but I cannot find the "new thread" button, somebody please help me here. Anyway, my message is: I changed spark plugs and see that they are slightly sooty, not a nice grey as they should be. Looks like I am running a little rich, all I can see on my carb is the idle setting knob, no main jet adjustment, how do you adjust the mixture?

[Mo]

Tartansailboat,

Shawn Stanley has a pic in post #15; if you look at his throttle cable there is a black piece of plastic on it. Look just below and slightly rearward of that little black piece and you will see an adjustment screw with a spring on it. That is the adjustment for your mixture.

Screw it in all the way the back it off 1 and 1/4 turns. Start the engine and let it warm up a bit. Try to smell the rich running engine. Back the screw off about 1/4 turn at a time until you don't smell it anymore....once or twice might do it.

After that you will want to ensure the engine starts well COLD with choke then stays running when you push the choke cable back in. This might take trial and error but you will get it set up. Just use some caution not to back that screw out all the way initially.

Hope that helps. ...by the way, just by looking at the plugs you are using I don't see them being "hot" running plugs. The hotter running plugs have a larger base. Your carb adjustment might be fine if you don't smell the richness... Hotter running plugs are capable of burning more in the combustion chamber as the plug fires....

To start a thread you click on a subject....ie "troubleshooting" and up in the corner will be a tab for "start a new thread"

[tartansailboat]

Maurice, thanks for the help. My plugs are the RJ12C that Don sells, is there a hotter plug? Also, I see the adjustment screw but I thought that adjustment is for idle speed, is there another adjust for that? Screwing it in makes the mixture richer or leaner?

thanks for the help in finding a "new thread" link for us computer disadvantaged folks.

[CalebD]

Tartansailboat,
To start a new thread you need to be within a forum or sub forum. In this case the 'Ignition' forum would make sense. Then the 'new thread' button appears above the thread list.
No harm, no foul though.

To answer your question about sparks, I've begun using Autolite 437 spark plugs which are supposed to be hotter and have been impressed with how little they seem to soot up the way the Champion RJ12C plugs did in my old engine.

Which Tartan do you have?
I'm in a T27 from 1967.

[tartansailboat]

Caleb, thanks for the directions on starting a new thread, I think I finally got it. I have T30, hull 127 circa 1972 and sail out of SF bay, lots and lots of wind. I just put in the new RJ12C from Moyer, engine runs very well just noticed more black soot on the electrodes than I recall seeing when I last changed the plugs in 2008. I think I will try to lean out the mixture to see if that cures the problem before I spring for the new plugs. I remember when plugs were $1 each, not any more.

My water pump just sprung a leak at one of the seals, water drips out of the weep slot. When I changed the impeller and saw just a little scoring of the shaft and was going to get a new shaft and seals but Ken suggested that the water pump which was 39 years old may be worn out as well. After 39 years, that pump doesn't owe anyone anything, so $250 later this week, I hope to get that fixed.

[CalebD]

TS,
I've used the RJ12C plugs for a number of years. Always seemed to have fouling issues with them though. Less so with the Autolite 437s so far. I have found the Autolite plugs for under $2 per plug.
I hope the mellifluous Ken talked you into getting the new Moyer water pump without the grease cap fitting?
I'd love to check out windy SF Bay sometime. We mostly race up the Hudson above the Tappan Zee bridge. Quite a few T30s where we are.

[domenic]

Rust, The pictures you posted look like my engine. Two things are different...flame arrest, breather tube, and glass fuel bowl. Outside of that it is the same engine. My boat is a 1968.

[Dave Neptune]

Plugs

Tartan, your plugs look good on the porcelin and that indicates that your jetting is about right. The bit of dark on the ground and edges of the plug look as if the idle is a bit rich and turning the screw out a 1/4 turn or so should be fine. Note that if your idle is about right on an updraft carb it should be a bit hard to start, that is why the choke is so very important on the A-4. There is also no acceleration pump to give a few squirts to make starting cold easy. If you need to use the choke a "bit" for a minute or two after a cold start your about spot on!!!!

I am still running the J8's in my 42 year old beastie and it runs great. From the look of your plugs I wouldn't go any hotter, perhaps a few more thousandths of gap will also make them act warmer at idle. Just the nature of a "load duty" low compression motor.

Dave Neptune

[domenic]

I talked to Dick Valdez this past year.(He was Columbia Yachts.) Dick told me about a trip they took to Mexico, and their A4 sucked in some junk, so rather than spend money having the company clean it out, they just replaced it with a new A4. Their cost of the engines at the time was only $500.
Dick also said, he has never heard of a fire problem with the A4. Columbia built 30,000 boats.
A diesels the same size as the A4 has less HP...and I don't know any owner who can repair, or rebuild a diesel.

[marthur]

I have a 1964 drop in spare, a 1969 in tough shape (needs new bearings, crankshaft, etc but castings and some other parts are all in excellent shape) and a 1977. The '69 and the '77 both have excellent compression so I am good to go for a while!