7.5cc in a Dumas Hawk 3.5?
#1
Senior Member
Thread Starter
Join Date: Dec 2006
Location: Franklin,
IN
Posts: 260
Likes: 0
Received 0 Likes
on
0 Posts
7.5cc in a Dumas Hawk 3.5?
I am in the process of building a Dumas Hawk 3.5 outrigger. I know that Dumas recommends a 3.5 engine for it, but I have a 7.5 K&B with a tuned pipe lying around. Has anyone put a bigger engine in this boat? And what, if any, would be the problem with puting it in there? It will fit just fine with just a little modification to the engine mount. Any input would be greatly appreciated.
#2
Senior Member
Join Date: Jan 2007
Location: Las Vegas,
NV
Posts: 1,262
Likes: 0
Received 0 Likes
on
0 Posts
RE: 7.5cc in a Dumas Hawk 3.5?
The boat wont take it, even most $100 21's would slaughter that K&B.
Give John Knight a shout, Hes got a few hot 21's hes looking to unload right now, you can reach him here [email protected] (if it was me, ask him for the CMB 21RS motor hes holding) Iv bought 4~6 motors from him in the past 2 or 3 weeks, and i love every one of them, Best 45 iv ever had came from him, older gold head cam H motor, I got it used from him for cheap, Hes more or less a rigger expert, and predicted my mongoose with his motor and the prop he selected to run 75mph, I came back with a solid 75.2 mph and have been buying up all his motors since then, recently got a 90evo2 motor, he tossed in a 101 P/S and some spares... Take ANY advice this man offers you...
Give John Knight a shout, Hes got a few hot 21's hes looking to unload right now, you can reach him here [email protected] (if it was me, ask him for the CMB 21RS motor hes holding) Iv bought 4~6 motors from him in the past 2 or 3 weeks, and i love every one of them, Best 45 iv ever had came from him, older gold head cam H motor, I got it used from him for cheap, Hes more or less a rigger expert, and predicted my mongoose with his motor and the prop he selected to run 75mph, I came back with a solid 75.2 mph and have been buying up all his motors since then, recently got a 90evo2 motor, he tossed in a 101 P/S and some spares... Take ANY advice this man offers you...
#3
Senior Member
Thread Starter
Join Date: Dec 2006
Location: Franklin,
IN
Posts: 260
Likes: 0
Received 0 Likes
on
0 Posts
RE: 7.5cc in a Dumas Hawk 3.5?
Thanks for the reply, but I was trying not to spend even more money. Figured I would just use what I had. I spent a crap load on another 26cc Zen powered outrigger last week. So I was just building this one for fun. Question though, If some .21 would slaughter the K&B .45 then how would this boat hold up to those and not the K&B?
#4
Senior Member
Join Date: Jan 2007
Location: Las Vegas,
NV
Posts: 1,262
Likes: 0
Received 0 Likes
on
0 Posts
RE: 7.5cc in a Dumas Hawk 3.5?
the 7.5 is larger and changes the roll point on the hull, it makes then hard to drive, plus the larger prop you would need would make the boat super squirrely, post a pic of your 7.5, depending on what you have, I might swap you for a good 21. and prop for that rigger.
#7
My Feedback: (12)
Join Date: Jun 2004
Location: Columbia,
SC
Posts: 8,044
Likes: 0
Received 0 Likes
on
0 Posts
RE: 7.5cc in a Dumas Hawk 3.5?
ORIGINAL: mhayes462
Thanks for the reply, but I was trying not to spend even more money. Figured I would just use what I had. I spent a crap load on another 26cc Zen powered outrigger last week. So I was just building this one for fun. Question though, If some .21 would slaughter the K&B .45 then how would this boat hold up to those and not the K&B?
Thanks for the reply, but I was trying not to spend even more money. Figured I would just use what I had. I spent a crap load on another 26cc Zen powered outrigger last week. So I was just building this one for fun. Question though, If some .21 would slaughter the K&B .45 then how would this boat hold up to those and not the K&B?
Your K&B .45 is an older design engine. Many of the newer .21s do have considerably more power and are significantly lighter. Getting a rigger trimmed to run right can be a challenge. If this is your first, you would be much better off sticking with an engine that's in the appropriate size range. Since money is an issue, perhaps selling the .45 and putting the money into a decent .21 would be an option?
#8
Senior Member
Thread Starter
Join Date: Dec 2006
Location: Franklin,
IN
Posts: 260
Likes: 0
Received 0 Likes
on
0 Posts
RE: 7.5cc in a Dumas Hawk 3.5?
OK thanks. This is my first rigger. I do have a full mod Zen 230 powered 43" v-hull. So Im not completely new to boats, just riggers. I do not race though, so Im not worried about all the details that go into setting up a boat for that. I just do this for fun and I also like a lot of speed. You do make a good point about the weight and balance issue, I can understand that. But is there that big of a difference between the 2? And as my engine is an older design, and the newer 3.5's have more power wouldnt the 3.5 actually cause more issues with the overpowering department of it?