Thanks Thanks:  0
Likes Likes:  0
Page 1 of 2 12 LastLast
Results 1 to 10 of 16

Thread: Mild hop-up of a Merc 350 . . .

  1. #1
    Team Member smittythewelder's Avatar
    Join Date
    Apr 2005
    Posts
    393
    Post Thanks / Like

    Default Mild hop-up of a Merc 350 . . .

    Anybody here ever race the old 30" two-cylinder Merc? I saw a couple of the four-cylinder 650 version in the F classes, but only one full-race 350 with megaphones for COH. I think a couple of guys ran 350s in C Service when the rules were opened up in the Seventies. Right now I'm Googling to see if I can find anything on the stock motor, how long a model run it had, lower unit ratio, etc..

    Anyway, a guy is wondering about getting some more snort out of a 350 for a playboat, gas-and-oil, no stacks. I would imagine he could carve a little more exhaust timing into the ports and install a slightly larger carb. Does anyone here have a guess what he could look for as to rpm power-peak (so we can make a rough estimate of appropriate propeller pitch)? Before he starts grinding, we want to make a wild guess about the prop pitch so I can ask Ron if such a prop can be found. Of course the guy wants a guess of horsepower, too.

  2. #2
    Team Member
    Join Date
    Dec 2004
    Location
    Toronto, Canada
    Posts
    96
    Post Thanks / Like

    Default

    There is not a lot to work with because of the design of that motor. A better choice in my view of a similar size motor would be the yamaha/mariner 40 hp 2 cylinder.
    I don't know if anyone has tried to mod one of these, but it appears to be a much better design.
    https://www.thehulltruth.com/attachm...0739&stc=1&d=0

  3. #3
    Team Member
    Join Date
    Mar 2005
    Posts
    559
    Post Thanks / Like

    Default

    Smitty:

    Get hold of Chris Hellsten. He can accept PM's on Hydroracer. May be registered here also but have not seen his name. His Dad, Pete, owned one of these back in the day that won the APBA Nationals several times, once with him (Pete) driving I think, and another with his Daughter Kristi. If Chris was aware of the mods that were done and remembers, he may be able to help you. I doubt there were very many mods allowed as the Speeditwin guys were at war with the ones trying to use the Merc and probably would not have allowed many if any as there were several of them on the PRO Commission at the time.

  4. #4
    Team Member
    Join Date
    Jun 2005
    Location
    Eastern PA
    Posts
    661
    Post Thanks / Like

    Default

    Seeing that's merely an enlarged Super Hurricane, there are lots of mods you can do and they will make a difference. I modified one with external reeds and dual carbs years ago that was a runner.

    In the photos I used a Merc 25 tower initially (with a driveshaft adapter), but props were not available. I then used a Mark 55 tower. Still very light, even with the E starter.

    Jeff
    Attached Images Attached Images    
    "We live at the bottom of an ocean of air." - General Marvage Slatington

  5. #5
    Team Member smittythewelder's Avatar
    Join Date
    Apr 2005
    Posts
    393
    Post Thanks / Like

    Default

    Thanks, fellas. Hounddog, you may well be right, but the idea is to use an old, cheaply-acquired motor and not carve-up (and maybe screw-up) a perfectly good pleasure boat engine just for occasional use on a little lake-racer/playboat. Thanks for the tip Bill, and I do remember the controversy that attended the addition of Mercs to C Service. I have one of the Y80s lightly boosted, not to Restricted B levels but more zippy than a stocker, and have hinted to the guy that something light and compact and with a racing lower unit and good prop would give him a lot better powerplant. Jeff, that's a neat piece of work, and I'll point the guy to your photos. But you say you couldn't find a good prop without using a Quickie. That's an issue we'd have to figure out before he tears the engine down and starts making chips.

    And just to add confusion, he's now started talking about a 35hp Johnson from the Sixties, so who knows, LOL.

  6. #6
    Team Member
    Join Date
    Jun 2012
    Posts
    80
    Post Thanks / Like

    Default

    I think there is a CService Mercury in Mark Suter's collection. I'll liik later.

  7. #7
    Team Member
    Join Date
    Jun 2012
    Posts
    80
    Post Thanks / Like

    Default

    Quincy Looper Racing site, Mark Suter collection page first and second pictures from the bottom . Bonus just for you, it has an Anzani flywheel.

  8. #8
    Team Member
    Join Date
    Jun 2012
    Posts
    80
    Post Thanks / Like

    Default

    Here's one running pretty well out front. Took me a while to find it .
    http://hydroracer.net/forums/forum/m...n-up-aof/page2

  9. #9
    Team Member
    Join Date
    Jun 2012
    Posts
    80
    Post Thanks / Like

    Default

    Lots of pictures over a few pages,
    http://www.boatracingfacts.com/forum...rd-quot/page23

  10. #10
    Team Member bobvdinghyracer's Avatar
    Join Date
    May 2005
    Posts
    18
    Post Thanks / Like

    Default

    couple pics of a 35hp twin on a mk20 leg used mk30 pan cut down for adapter only mod was a drivshaft adapter ... easy to do this would also work for a ke/kf/ kg leg and a ab quickie ... as far as props not hard to adapt just about anything you can come up with the motor pictured was built for a buddy using a merc 13 pitch bronze stock prop , i also have 1 on a cut down mk20 leg with a kg gearbox at bottom 16/21 gotta find pics of it

    Name:  Copy of IMG_20160303_145243416.jpg
Views: 336
Size:  215.6 KBName:  Copy of IMG_20160216_223551231.jpg
Views: 322
Size:  228.8 KB

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. 75hp merc triple carbs on 40 merc
    By BRzuki in forum Technical Discussion
    Replies: 12
    Last Post: 02-04-2013, 02:18 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •