Glow plug, Not burnt, but dont lite

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Try a X-437 or a lifting prop like a X-1437

 

[MikeP]

Turn up the heat, hotter motor = richer mixture=more power. You should be turning a x440-3.

 

[topfuel443]

How much is the carb open when the boat is able to maintain an idle on the bench without any extra throttle? I run a MAC with the nitro pipe at 8.25 inches, the head set at 8 thou. running 60% redmax and turn the hell out of an H7 prop in my rigger. I have been running the same mc9 plug for the last 2 gallons of fuel. You said when the boat runs out of fuel it kills the plug right? or does it do it when you let off the throttle after running high rpm? If you are running the tank completely dry then it will probably kill the plug every time b/c it goes very lean at the last minute (hence the reason the plug doesnt have the discoloration, its not running lean long enough, only for a few seconds as it runs out of fuel). If it kills the plug when you back off the throttle from high speeds, I would say its a little to lean, although it sounds like its rich enough b/c its spitttingfuel out of the carb. I run the stock carb and in order for it to run on the bench without any extra throttle the barrel has to be half open. It idles very high, as do most of the other macs ive seen. I no that Jerry Crowther takes the element and strecthes it out until its sticking out the end of the plug.......It works for him, not sure why he does it but it works.

~ James

~P.S. Do yourself a favor and get rid of the O.S. needle, I went through two of them before I realized it was causing my only big problem with running this engine. I went with a bob violet needle and the problem went away.

 

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I use the OS needle valve on my Nova Rossi .21 mono in a Microburst and an OS needle valve in my .21 UL Road Runner w/no problems at all. I actually went over to those because I kept having problems w/the Bob Violet. Interesting tht James had the exact opposite problem as I did? Wierdness!

 

[nitrotoys]

Ok guys, been a hell of a time with this, BUT I went with bigger fuel lines, stuck in some R5 plugs, gased it and went without a problem. The engine wasnt getting past 160, I couldnt go leaner as it would bogg down, so set back to where i had it, Stuck a needle valve in the water pick up and started to close it till it ran 220.( our pond temp is at 57) Now that the motor is up to a nice temp, i didnt go through a R5 plug, for ***** i stuck in a MC9 plug and ran a tank, end of tank it was bad.

same set up, gased and stuck the same R5 in it and ran another tank, Stoped and checked, still good.

the carb is open just between 1/4 and 1/2.

and it Killed the plug after a run, I could putt around with it after a few hard full throttle runs and be fine, just when i shut it down. Now that this is kinda solved the problem, i can start seeing if i can turn a 440-3 blade,

Now i have the pipe set at 8 inches, some said shorter, some said longer.

longer pipe does what?? Turn on later, or sooner??

thanks for all the info.

 

[topfuel443]

rcboats, That is weird, guess we both got bad batches of each in our first attempts.......what ever works right? ;D

Glad you semi found the problem with the glow plug issue. as for the pipe length, Im not sure about the mono thing cause you guys turn smaller props than we would on the riggers. 8.25 is as short as i could go with the h7 and a hair over 8 inches with an h4 prop. ......tinker..tinker...tinker youll find the best combo.

~ James

 

[nitrotoys]

With the temp at 220, That X438 sure makes that boat goo. I know the 440 will not let it turn the RRRs it needs, I havent GPSed it, But i would say mid 40s.

So might just play with the 438 and see what more i can get out. This is a SD2 Ducer, Weights alot more than a rigger. Hell the carbon inlay probably weights more than a rigger.

Damn them R5 are pricy compaired to the MC9s.

But if they dont blow, i am saving money.

I have always had good luck with OS plugs.