ML SX400 Nitro Build

[Samuel Hagan JR]

Is t hat the A/A slant or straight. Also is it stock.

 

[anthony_marquart]

Not going to move engine.. not that far off.. Just going to add a little weight on the forward inside of sponsons or in front of radio box,. If I built it again I would would move it maybe 1/2 in forward.. but it's not bad enough to do all that. The engine is a stock AA 45 with the straight carb,.. So far,.. mine runs great.. I run on the rich side with a short pipe. just my style.. I have had a few plugs fail but none have had the coil go through the engine.. the few that died were broken about midway down the coil.

Might not even move engine,.. might move tanks back if I did it again.. I had faster runs,.. but this was good for video..

 

[anthony_marquart]

Any comments guys. Would like to hear your suggestions.

 

[Jim Caldwell]

Detoung the 450?

 

[anthony_marquart]

The 450 from MS or the one I was running? Right now just have props that I did. I took some of the tongue off, maybe not enough.. I'm sure it will be removed on the props from Mark,..

 

[Ken Webb]

You say your pipe is set at 9 1/8 to 91/4. Are you measuring from center line of engine? Reason I ask is because K&B yrs ago in instructions for their tuned pipe measured from the exhaust flange on the engine.

 

[anthony_marquart]

measured from the glow plug to the seam,.in a straight line..

 

[FloridaScaleBoater]

As long as you measure the same way every time,, doesn't really matter.

Everyone does it different??

I measure from the cylinder centerline to the widest point of the pipe.... Reason? look at how the measurement "Can" change if you have a lot of angle in your pipe, when measured to the glow plug.

 

[anthony_marquart]

Yeah. To the engine cl would be more accurate. Maybe my real short setting was not as short as I thought. Got my muffler on the macs pipe. Will try that next week

 

[Samuel Hagan JR]

If it runs that good stock in just may restore my faith in A/A.

Looks good. Get the flighty out of it and let it rip. Any idea on speed.

 

[anthony_marquart]

I don't have it on radar yet but comparing to other boats I did radar I would say 62-63. Heck. Let's be conservative and call it 60. Yep the motor has deck height about 0.010 and bone stock. Running a little rich. Used one plug sat. Cracked coil in the middle and was still there in the plug.

 

[Samuel Hagan JR]

60 MPH is fast in heat race trim.

Make a trip to Evansville IN next year if you can.

 

[Gale54]

60 MPH is fast in heat race trim.

Make a trip to Evansville IN next year if you can.

Or Madison

 

[anthony_marquart]

Next test report.. about 55 degrees,.. nice air for nitro motors..

- added weight in front of radio box to get CG corrected. It was not enough to move the motor,.. but if I built again I would move it one inch forward.

-Switched from AA pipe to Macs45 nitro pipe with Rumracing stinger. set at 9.5 from glow plug center.

-Mark Sholund x450 prop.

I reset up the boat with the strut dead flat and the bottom of the hull level with set up table. After running and one blow off, I lowered the strut 1/16 and totally corrected the problem.

The boat may be a bit higher on top end but the biggest improvement was the throttle response and the better CG made the boat handle MUCH better.

No more sagging in the corners.. just a small bit of hop in the corners to get rid of.. Im sure some TF work will eliminate that.

Thanks for all the guy on the forum that helped me get this running.. it would take months instead of weeks without your help to get a boat running like this..

Oh yeah,. and it's still prolly a bit rich.. The plug was greyed and just barely a little browning on the face of the plug... Did not take a single plug... I still have a problem with dieing when the second tank is half empty.. May need to run the smallest hopper I can find.. but the capacity is large... right now I've very happy..

Next steps.. what do you guys suggest? props props props? I have some prather 230, 235 and 245 to try.. the 245 looks too big... but who knows..

The guy running the camera did his best..