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Old Oct 05, 2005, 03:53 AM
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Joined Sep 2005
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Please help... Having trouble keeping twin nitros going

Well I got this boat built and and have taken it though two sea trials
S.T. Problems
Sea tial #1 I realized my gas tank might be to high and I was a siphoning affect and flooding both motors. Also shafts were not allined proper and there was so much vibrations the struts broke and one stuffing box broke free from the hull and started taking on water, thank god shes a big boat
what I did. I relocated both stuffing boxes and lined them best I could with the motors in place, and I put in a smaller fuel tank as low as I could to cobat the siphoning affect.

Sea trials #2 Theres about 500 cc of gas though the motors I can start the motors fine and get them reving nice but when I put the boat in the water at first Its strong, 1/4 thottle the boats already doing 15-20 miles and planes out nice about 30 seconds to min the throttle response gets weak and one motor will stall no mater how much I jump the thottle. Then just listening to the one motor it sounds weak and a few seconds later the other motor cuts out, no mater how much I play with the thottle to try and save it from stalling, there has been a few times I made it back to land on one motor though .

Here is a pic I appreciate any help I can get I have never built a boat before this is all new to me thanks

my needle settings are 1/2 turn open any more and I am spitting lots out of the tail pipe.
Jamie
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Last edited by scalecrazy; Oct 08, 2005 at 01:34 AM.
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Old Oct 05, 2005, 03:55 AM
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Joined Sep 2005
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Sorry about the size everybody here are the pics
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Last edited by scalecrazy; Oct 05, 2005 at 04:26 AM.
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Old Oct 05, 2005, 09:08 AM
Boats on the brain!!
green-boat's Avatar
Arnold, Mo.
Joined Jul 2005
4,611 Posts
I have never seen that setup before pushing fuel from a large tank into a smaller one. I did notice that the fuel lines are rather long. I have come across instances where vibrating fuel lines will cause bubbles to form in the fuel causing the mixture to lean out. My suggestion would be to use one fuel tank located closer to the engines and shorten up those fuel lines. If that is a "clunk" tank, it has been installed backwards, in front of the engines. Maybe this is the purpose of the smaller tank to ensure a "clean" fuel supply. If the tank was to be mounted behind the engines then it would be correct. Just an observation.
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Old Oct 05, 2005, 10:21 AM
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Newburgh New York
Joined May 2005
823 Posts
i don't know much but i think i see that your running both mtrs on one servo.
would it not be better to have two servos off a "Y" conector to the reciver.
just a though.
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Old Oct 05, 2005, 12:39 PM
Grumpa Tom
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United States, CA, Los Angeles
Joined Sep 2003
23,869 Posts
You have a really difficult setup there. Some problem areas I see are:
1) Extremely long exhaust piping = a lot of backpressure.
2) Extremely long fuel lines = inconsistencies in fuel draw
3) Fuel tank is below the centerline of the carb = drawing fuel uphill.
4) Dual tank system = alternating low and high fuel pressures.

Another item to check is your water cooling. Are you getting a nice flow of water exiting the boat? If not, nitro engines will stall from excessive heat.

This is quite a challenge you have. I'm sure it will get sorted out but it will probably takes lots of testing.
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Old Oct 09, 2005, 02:33 PM
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Joined Sep 2005
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Hi guys thanks for the the suggestions in the end after tanking the t-maxx out to get rid of some frustration with the boat it dawned on me, the 2 pressure lines would over pressurize the big tank causing the little tank to over flow and also gave unequal fuel delivery. So I figured I would install 2 new tanks two give the boat simplicity and symetry also turned the tanks around thats it, cost me 12 bucks for that fix thanks for the info. She gets lots of water flowing out evenly,nice power I am still breaking her in so I haven`t seen her at full power I don`t have a radar gun but what I have seen of other boats I would guess this boat goes 30-35 mph I think I will have to install turn fins.

But all in all, my third sea trial was a success, she was bone dry and went straight as an arrow so I think I did a good job.
Sea Trial 3 pics
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Last edited by scalecrazy; Oct 09, 2005 at 03:03 PM.
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Old Oct 09, 2005, 05:42 PM
Grumpa Tom
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United States, CA, Los Angeles
Joined Sep 2003
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scalecrazy, right on! Glad you got it sorted out and it looks sweet on the water! Can't wait to see it with its lid on cruisng on the pond.
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