The PT Boat Forum
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ť Forum Category: PT Boats of WWII
http://www.ptboatforum.com/cgi-bin/MB2/netboard.cgi?cid=101&fct=showf

ť Forum Name: PT Boats - General
http://www.ptboatforum.com/cgi-bin/MB2/netboard.cgi?fct=gotoforum&cid=101&fid=102

ť Topic: Anyone need a Holley PT Boat Carburetor?
http://www.ptboatforum.com/cgi-bin/MB2/netboardr.cgi?cid=101&fid=102&tid=4866

For sale on Ebay is a Holley Down draft carburetor. Seller is asking $200.
[url]https://www.ebay.com/itm/312888854065?ul_noapp=true[/url]

Posted By: Travis B | Posted on: Dec 14, 2019 - 11:30am
Total Posts: 126 | Joined: Nov 23, 2019 - 10:11am

I think the guy is trying to use PT boat to make a sale. The model, DD-5, is not what was used on the PT's Packards:

Posted By: Jeff D | Posted on: Dec 15, 2019 - 5:51am
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am

Looking at the pictures on EBay this carburetor seemed nowhere near large enough for a Packard even if it does have 'V12' stamped in its body. A little research shows the Holley DD-5 is for a V-12 marine engine, but it's a Scripps V-12 Model 302 H.Q. It uses two of these carburetors and is rated at 275 HP. From the fuzzy pictures in this operating manual it looks like a flat-head engine and from the specifications (four main bearings, etc.) it is not a high performance engine. Still, it is a V-12 marine engine that I had not heard of before, so, it's an interesting find.

[url]https://books.google.com/books?id=6rOqCoJISLQC&pg=PA20&lpg=PA20&dq=holley+carburetor+model+DD-5&source=bl&ots=LjQYW9wIki&sig=ACfU3U02AVMmFzTkOGJwX2MLSZ2ryOpRuA&hl=en&sa=X&ved=2ahUKEwiXxLPD97fmAhVLY6wKHaeSCQYQ6AEwCXoECAwQAQ#v=onepage&q=holley%20carburetor%20model%20DD-5&f=false[/url]

Randy McConnell (Randall J. McConnell III)

Posted By: PRJM3 | Posted on: Dec 15, 2019 - 7:29am
Total Posts: 94 | Joined: May 25, 2009 - 2:47pm

Nice find, thanks Randy. If nothing else, the seller could at least claim that the carb type was used on WW2 vessels.

Posted By: Jeff D | Posted on: Dec 15, 2019 - 10:28am
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am

Jeff, do you know what WW2 vessels this engine would have been used in?

I might have been premature in saying the Scripps V12 was not a high performance engine. After a little research showed that the engine was used in high performance wood boats of the 30s made by companies like Gar Woods, Chris Craft and others. There are pictures online of numerous restored installations and at least one video of a Scripps-powered Gar Wood starting up and leaving the dock with the sounds that only a big V12 can make. It might have been older technology, such as a flat head with cylinders cast in blocks of two and only four main bearings, but 895 cubic inches helped make up for that. One site claimed 316 HP and the manual I linked previously said 275 HP at 2,200 rpm.

Randy McConnell (Randall J. McConnell III)

Posted By: PRJM3 | Posted on: Dec 15, 2019 - 6:32pm
Total Posts: 94 | Joined: May 25, 2009 - 2:47pm

Would this be correct for the PT boat?

[url]https://www.ebay.com/itm/WWII-Holley-B-25-Carburetor-1685FR-Floatless-Wright-R-2600-Downdraft-WW2-WWII/372797834261?hash=item56cc7b8415:g:6HQAAOSw7Sxdm-0P[/url]

Posted By: Travis B | Posted on: Dec 16, 2019 - 4:30am
Total Posts: 126 | Joined: Nov 23, 2019 - 10:11am

Hey nice find Travis! It's the right model number and looks the same as the pictures from the manual.

I don't know Randy, maybe Al would know.

Posted By: Jeff D | Posted on: Dec 16, 2019 - 3:18pm
Total Posts: 2200 | Joined: Dec 21, 2006 - 1:30am

Remember that the listed carb is for an aircraft mounted engine that will be operating at a range of altitudes, rather than just sea level. Also, Holleys were applicable across a range of engines, but that does not mean a direct swap was enabled. Re-jetting was pretty standard. I do not know what the 'automatic mixture control" entailed, but I would guess that it would be different for a boat than an airplane.
Last point, boat engine are always under load, unless in idle, autos not so, and planes are outside of my experience, but I would expect them to be different than boats.

Posted By: JEno | Posted on: Dec 17, 2019 - 6:29am
Total Posts: 72 | Joined: Oct 13, 2019 - 9:52am