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HPI .25 engine questions/issues

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T

TacRacing

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I got the Savage new from the great Bruce at RushRC.. and I have some questions about this engine..

1. The motor didn't want to idle properly on breakin.. but I got through it. Once I got it broken in I replaced the glowplug with the great OS #8. I started to tune for performance, and I got it there. It was fast.. and not too hot (i temp gunned it) and smooth. After the tank went dry.. I let it cool off and started it again about 15 min later. It was groggy... slow... idling funny.... and running a little hot. Why is this??

2. Why is it that when I remove the glowplug, the bottom of the plug is brown like it was too hot maybe?? and the top of the piston looks brown?? I have had pretty good luck apparently with engines, and I have never seen this before.
My engine experience is with : TRx .15, TRX 2.5, Mach .15, TT .21, and the crappy MegaTech .16.

3. I run the motorsaver airfilter and now the ribbed pipe.. do you guys have any suggestions on making sure that I get some life out of this motor??

Thanks,
adrian
 
What fuel are you running? Sounds like the engine is getting fouled from running too rich. If it was too hot, it would have a greyish look to the coil.

Also forgot to ask when you say "a little hot" what's that temp? How are you breaking it in? Are you running it slow with a few blips? Bess method?(heat cycling)
 
Last edited:
I am using Trinity Monster HP 20%.

I think the glowplug does have some gray to it.. they all do after a while... haha

when I say the bottom of the plug though.. I am talking about the flat surface of the actual plug, not the heating coil.

thanks,
adrian
 
I forgot to add...

I believe that the highest temp that i took of the engine was 300... so I don't think I am running it too rich. That was the day that it was running so crappy, so I leaned it out.. better.. leaned it out..... better.. leaned itout.... really screaming.. checked temp.. too high.
This has been a while though.... so I can't be 100% on the 300 degree part.. but it was high.
 
300 is definitely too high for these motors. A good temp range should be anywhere from 220-260. I like running my motors at 2-220
 
I had problems breaking in my engine also. turn all neddles to factory settings. I also ended up heating the head with a hairdryed and that brought it to areound 170. from then on it was a lot easier to start and let idle. I did have to occasionaly blip the throttle but it worked out great. and you are running the first tank of gas while the savage is on a box so the tires are off the ground right.
 
Yes, I used the railing on my front porch.

I have already broken it in...

Actually, I have already run about a half gallon through it.

I am concerned about burning up the motor and/or ruining it.

Also, I am worried that I will never get it to stop leaning out so bad halfway through the tank.


adrian
 
does your tank have a primer?

the older models do..... check it and see if it has the fuel feed in the back of the tank.

HPI redesigned it so that it would fix that problem.

Also check your pressure line for leaks.
 
No primer on the tank.

I don't think it is an air leak because I don't have the problem for the first 1/3 of a tank. I know engines lean out a little when the tank gets lower, but man, it is really leaning out.

adrian
 
Tac mine does the same thing! I think happens more when you save your truck after a flip. The motor sucks in air and then for some reason the truck starts to burb and then run really high.

What I want to know is that I got the same motor saver, and ribbed (for my pleasure) pipe, and my Savage 25 is running really sluggish. I heard these things can walk wheelies and mine just won't unless I am climbing a hill. Is it because of the gearing?

Is it big spur gear little clutch bell, or little spur gear big clutch bell?

Tac call me when you read this!
 
its big spur little clutch, high ratio=wheelies low ratio=top speed

to find the ratio you divide the spur gear by the clutch bell.

so 52/12 = 4.333333 so you get wheelies

and 47/19 = 2.47 so you get a high top speed
 
Carbon_Savage418 said:
its big spur little clutch, high ratio=wheelies low ratio=top speed

to find the ratio you divide the spur gear by the clutch bell.

so 52/12 = 4.333333 so you get wheelies

and 47/19 = 2.47 so you get a high top speed
Click to expand...

LOL.. Thats right, and some good info, but whats that have to do with Tacs engine running lean??? lol :cheers:
 

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