Need help

[P THOMAS]

How in the world can a motor be that rich and still starve?

This is what the motor acts like when you dont have large fuel lines and 1/8 tubes in the tank.

The id of the fuel lines will restrict the flow too much.

I went thru this like you, even took off the needle and ran the line direct to the carb and it wasnt too rich to run.

 

[EatMyShortsRacing]

I think one of the clues here is the OPS works fine in this boat.... and the problem has followed the engine from one boat to another.

*yes I will admit a MAC will be thirstier than an OPS*

Thats what is leading me to believe that it is a plug / fuel / compression issue. I dont think the motor is actually starving. The plug element is being blown away and causing the appearance of fuel supply problems.

Also I am guessing this boat has one tank only? Header tank may help too.

I will have to re measure my engines to see if the .011" clearance is right too but maybe another 0.002" might be the go.

Sometimes you wish you just had that boat in your hands at the lake and you know you would have it circulating in no time!!!

 

[Glenn 787]

Jason,Dismantle the tank, drill the end cap and stopper to accept 5/32 brass tubing for the fuel line. (if you use K&S brass tube - anneal it first). Run the large dia. fuel tubing thru to the needle valve and then to the carb.

Tim.

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How do you anneal the K&S brass tube and why?

 

[P THOMAS]

[How do you anneal the K&S brass tube and why?

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heat it up red and let it cool then you can bend it

 

[tracerbob]

Whoa...that was a lot of info at once...
Let's see, I don't know whether my needle valve is course or fine. 

Jason

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The fine needle has some of the chrome plating removed from the top of the hex nut. Hope this helps.

 

[TimD]

[How do you anneal the K&S brass tube and why?

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heat it up red and let it cool then you can bend it

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Thanks Phil!

It's more likely to crack if you don't anneal it. It will save you some heartache later

 

[Anders_Martinelle]

Check so your rod and case don`t look as this:

https://www.intlwaters.com/gallery/albums/userp...10085/Case1.JPG

https://www.intlwaters.com/gallery/albums/userp...085/Conrod1.JPG

This was a problem with some engines.

I had it both with 84 and 67 engines.

You don`t feel anything if you turn it around but when you run your engine the rod scrubs the inside of the case .

Found this after i have tried everything to get them to run well B) .

Anders

 

[jasonspeedy]

Okay-the needle has no coloring, it's like dark steel, so I guess it's the fine one.

Yes Anders, the inside of my case and rod look EXACTLY like that!

One more thing, I might have caused some of the problem. I removed some of the skirt because it was bumping the crank, but I removed too much I think. When the piston is at TDC, there's @ .070" gap between the bottom of the skirt and the bottom of the exhaust port...oops? Is that bad, since at BDC both ports are open on the top?

Hope this makes since...I can clarify if I need to.

Jason

 

[Don Ferrette]

Okay-the needle has no coloring, it's like dark steel, so I guess it's the fine one. 
Yes Anders, the inside of my case and rod look EXACTLY like that!

One more thing, I might have caused some of the problem.  I removed some of the skirt because it was bumping the crank, but I removed too much I think.  When the piston is at TDC, there's @ .070" gap between the bottom of the skirt and the bottom of the exhaust port...oops?  Is that bad, since at BDC both ports are open on the top?

Hope this makes since...I can clarify if I need to.

Jason

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Time to order a piston & sleeve.

 

[jasonspeedy]

I forgot something.

I made the fuel, it's 60% nitro, 18% cool power, and the rest is alcohol. The plugs are MC-59.

One more thought...It shouldn't be this hard to make a stock motor run...either I've screwed up the motor by grinding on the skirt...or something in the system is malfunctioning in a big way...

 

[TimD]

Okay-the needle has no coloring, it's like dark steel, so I guess it's the fine one. 
Yes Anders, the inside of my case and rod look EXACTLY like that!

One more thing, I might have caused some of the problem.  I removed some of the skirt because it was bumping the crank, but I removed too much I think.  When the piston is at TDC, there's @ .070" gap between the bottom of the skirt and the bottom of the exhaust port...oops?  Is that bad, since at BDC both ports are open on the top?

Hope this makes since...I can clarify if I need to.

Jason

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SUB-piston exhaust induction at TDC can be very bad for performance.....

You need a course needle with a 67. The fine needles are for the 21's and 45's.

 

[boaterbill]

Whoa...that was a lot of info at once...
Let's see, I don't know whether my needle valve is course or fine.  I'm assuming that by stingering the black AB pipe I'm richening the mixture, which sounds good, and I've never thought about using larger brass in the fuel tank, that's a good idea too.  I've never considered the size of the pressure tap on the pipe, but I see how that could affect delivery.  Geeze, you guy's act like you run model boats or something.  I guess I need all the fuel and water I can pump...at least that's the idea I'm getting.  Thanks a bunch.  I'll try some of this stuff.

Jason

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Look at the top of the needle that is hexed, if you see brass on the top, like the chrome has been ground off. That is a fine needle. The coarse has not been ground on. If you have two different ones you'll see what I mean. Sounds to me you're running the wrong needle. If you have both out of the package flow them, the higher flow is the coarse. You don't have to remove the needles, you can see it on the hex top.

Bill

 

[Anders_Martinelle]

Remove some of the rod like this and you will be fine

https://www.intlwaters.com/gallery/albums/userp...5/After.mod.JPG

Anders

 

[Don Ferrette]

Remove some of the rod like this and you will be fine 
https://www.intlwaters.com/gallery/albums/userp...5/After.mod.JPG

Anders

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AFTER he replaces the piston & sleeve. .070" of sub port induction ain't gonna work.

 

[EatMyShortsRacing]

Yes sub piston induction is not good. Say buhbye to some horsepower. Probably not a bad idea looking for a new piston / liner..... But for starters.....

MC59 is too hot for 60%!!!

From the web:

This is the McCoy MC-59 Standard Long Plug (No Idle Bar) with a Hot element that's designed for use with Low to Medium Nitro Fuels, perfect for Helicopters.

You need at least a McCoy 8 but most likely a McCoy 9. This is why your plug is not lasting long at all. The leaner you go the quicker you will destroy this plug. That can happen in less than a lap.

AND (ducks for cover) I dont trust Cool Power.... Yes there have been many 'discussions' and there is really wasnt much of a conclusion but I think you can find much better oils to run. I dont believe this is the problem at the moment but you might want to consider even running a blend of oil putting a bit of castor in that mix 50/50 with the cool power (9% cool power 9%castor)

 

[Anders_Martinelle]

That`s true!!

But he still need to do it..

Sorry 0,07 inch????????

That is 1,7mm!!

Wow :blink: :blink:

New p/s is a must......

 

[EatMyShortsRacing]

Well a piston / liner will take time.... getting a McCoy 9 and throwing it in the boat he can do this weekend... see if there is any improvement....

 

[Anders_Martinelle]

A MC9 will not help.........

 

[Don Ferrette]

That`s true!!
But he still need to do it..

Sorry 0,07 inch????????

That is 1,7mm!!

Wow :blink:   :blink:

New p/s is a must......

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Yup, .070" gap is HUGE!

 

[Mike Byer]

did you hear the big sigh of relief?.......... I think that was AB.

Mike B