Vintage Speed

Finally got the GPS speedo out on the 1955 Atom Skier. The model 620 Gray Marine 4 flathead got the 14.5 woody up to 30.3 mph. Is this good...bad...or what? Gotta say...30 mph in that little boat feels like 70!

I don't have a tach, Gary. Thanks for the input.

That little one we had is in need of tuning and ran about 28 mph on gps.

Billy's back, now we need Pete!

How does one go about throwing a temporary tach on the old girl? I have never checked the prop for numbers either. That I will do in the daylight. But as for the tach...how is that done?

Got an old school analog Snap-On Tach/Dwell meter hooked up with a borrowed 12 volt battery. Alone in the Atom skier I got 31.1 mph at 3300rpm. Honestly, I don't need to go any faster than that in a 59 year old wooden boat. The motor sings and the wake is flat...what more can a guy hope for?

Nuts...I did not check the prop. Will do, tho...
But yeah...boat and driver happy! The passenger is having a good time too.

Great stuff! Awesome to see that little atom scooting along!

Nice looking (and running!) boat John! That picture is great, love the smiles. If you ever have a chance please post a video of the boat at speed, would love to heat that Gray wound up, and at idle at the dock.

The speed shot was taken by my neighbor, Judy Wagner riding shotgun with her hubby Randy at the helm of their '46 Higgins 17' utility. Sweet ride!
We were on Lake Beulah on a sun drenched Sunday afternoon.

John, no clue on the numbers. I think if you remove the castle nut and washer you might see the diameter and pitch embossed on the end under where the washer sits.

By the way, that castle nut and washer and pin aren't steel, are they? Kind of look that way in the picture.

You don't need a washer just a brass castellated nut and a stainless cotter key. I doubt you'll find any numbers under the nut,that's a relatively new thing,and that's an old Federal prop

The 3300 is good so I wouldn't worry about the prop. Still, it would be a good idea to send it into the prop shop. A 11" diameter is hard to find so it's worth sending in for a tune up. Your speed is just about there. You may get some more out of it after the prop tune up but don't expect much. I get about 34 to 35 out of my Atom but I have the Hercules model B (60 HP) which is lighter than the Gray. Have you checked the timing? With the vintage engines it was and still is common to get to WOT and have someone advance the distributor for max RPM/speed and then back it off slightly. Dwell can be set with the feeler gauge. Have you checked it? When you get the prop back, don't forget to lap it onto the shaft. The one picture shows dings on the shaft so someone has been whacking on it. Maybe he didn't have a prop puller? The washer is only needed when the nut goes on the shaft too far so the cotter pin hole will line up better. This does happen when the prop taper is too deep.

BTW, this vintage engine can be run WOT all the time as they were made for it. Think about an old gen set were they would run at 3600 all day long.

Sorry for the link but below what they are talking about laping the prop. I have been studying this as I will be installing my new 540 prop today

http://www.correctcraftfan.com/forum/forum_posts.asp?TID=12866&KW=proper+prop&PID=145077&title=proper-prop-installation#145077

Good luck.

A prop tune up John is just where a prop shop would make sure that the pitch is correct and the same on all blades and then check the balance. Don't take it to a marina they just farm them out and add their fee. Pete might know of a local shop,if it was a more modern prop, Delta Propeller a site sponsor would be a better choice.