Pearson Boats - Common Systems > Engine and Drive Train

A4 Owners: RPM Table

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Sea Haven:
Ed,
Thanks for the assurance, and I'll keep my eye on the oil consumption too. The smoke I saw was definitely not oil or steam. I bought the adjustable main jet last year when I purchased the rebuild kit. Now that I have the other "issues" resolved, I'll start "tweaking" it as you suggested. I'll have to compute the fuel flow rate manually for now.

Alma,
Do you have the KIWI prop?

Thanks!
"Sub" Ed

Alma:
Yes an adjustable main jet is key. The fixed jet was designed for the good fuel available 40 years ago!

There is also a carburetor housing mating surface upgrade on Moyer's site that I performed over the winter. The procedure addresses too lean a mixture at certain throttle settings. It is about filing the castings to insure they seal against the body gasket correctly. Check it out but go easy- it can ruin the body to remove too much material.

I have my main jet turned in so close to lean I see a need to use the choke in the Summer when starting up cold. With the old fixed jet I only needed the choke in freezing weather. I now use the choke to start in summer then push it in after a few seconds. I also noticed a big increase in "milage" too with the lean burning adjustable jet.

It isn't possible to get the same detailed tuning information we used to with spark plug visual charts with our modern fuel. The best we can do is note that all are the same and not sooty. I'm also running Pertronix ignition and that helps economy and smoothness too.

A friend who had some antique cars told me all flathead engines (like the atomic 4) consume more oil than we are used to. I know my old 4 can burn a lot of oil if I push it and I do see some oil smoke mixed with steam when the water is very cold but I also add an ounce / 5 gallons of Marvel Mystery Oil which might show smoke.  It keeps the whole engine from fuel tank to exhaust nice and clean.



Most important is prop fouling. I can tell when mine is fouled- everything vibrates- lazzarette hasps, ladder, engine cover, stove-



And after that little Great White was filmed near where we sail last week I've got the Heebe-Jeebes about lingering under the boat scraping my propellor!

Sea Haven:
All Shipmates regardless of iron genny,

The HOW and WHY you should take the time to do this:

How to Make an RPM Speed-Table for Your Sailboat

"Sub" Ed

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