Fuel tank info for OS marine engine - RC Groups
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Jan 16, 2006, 09:17 PM
Rocky Mountain High and Higher
PROACE's Avatar

Fuel tank info for OS marine engine

OK experts I need some suggestions. I bought a new OS .21 RG-M and would like to know what a resonable size fuel tank would be. Also are there any tricks to keep foaming fuel from leaning out the engine during a rough run? Prop selections too if anyone has experience with this setup.

The boat is a Dumas Deep-Vee 20.
The engine is an OS .21 RG-M with a Macs tuned pipe.
Thanks all for any help.
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Jan 19, 2006, 12:41 AM
all my boats are broken
ernest2's Avatar
hi! i'm no expert. but from what i have read and what was suggested to me, an 8 oz dubro or sulluvan tank is good enough, thou that will still depend on the hull if it fits or not
Jan 19, 2006, 12:42 AM
RC boat Rock Star
8 ounces. Octura X-437 to X-440 or a Prather 215.
Seeing how it's going into a mono I bent the pick-up tube to the right rear corner, don't use the clunk. If you're really that worried about not picking up fuel then use a 1 or 2 ounce hopper tank.
Jan 19, 2006, 07:32 PM
Rocky Mountain High and Higher
PROACE's Avatar
Thanks for the info. When it is finished I hope to post pics so I can get some constructive input before I take it out and sink it

Another question has come to mind also. Are the trim plates useful and how are they used correctly? What about balancing the boat is it like balancing a model airplane so to speak?
Jan 20, 2006, 12:02 AM
RC boat Rock Star
Good questions.
Yes, trim tabs are definitely useful. Mount them 1/16" above the bottom of the hull, easy to do if you have a piece if 1/16" ply to use as a guide.
Yes, you basically balance them kind of like a plane except for the wing part.
If you go with the hopper tank, place that over your CG on the right side if you can.
Jan 20, 2006, 06:51 PM
Rocky Mountain High and Higher
PROACE's Avatar
So would I balance the boat at the center of (front to back)? Also I have seen boats bounce up and down on the front like a porpoise. Is that a balance or trim problem or just the nature of that particular boat? I will be breaking in engine when I run the boat for the first time so maybe I can trim the boat during the same time.
Jan 20, 2006, 11:54 PM
RC boat Rock Star
Porpoising can be from several things, one is the balance being off, the strut being a little off vertically or at an angle. Start with everything with the driveline level with the bottom of the boat including the trim tabs. Your first runs might keep you busy getting everything dialed in from the carb to the prop. Take one step at a time.
Jan 21, 2006, 11:09 AM
Rocky Mountain High and Higher
PROACE's Avatar
Great info. Thanks, I really appreciate the help.

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