Problems tuning MP6 buggy w/O.S. Max RZ

[Badsneaker]

I cannot seem to get this buggy running right.

I do not know how old the engine is. I set the high and low needle to factory spec. I went 2.5 turns out on high, 1 turn in on low. Engine very rich. Leaned out both high and low. Engine seems to be loading up when I throttle. If I don't give it some small revs when its loaded up, it will die. Also as its warming up the engine changes idle, faster.

It does start right up on the starter box. I'm thinking maybe an air leak somewhere? The plug that I am using is a O.S 8. Maybe I should go to a 9?

I brought the buggy up to the track last Thursday to see if I could get some help. The low speed screw was bound up, very hard to turn. One of the guys gave me a hand trying to get tuned. They recommended to change the carb. I had another carb at home, so I changed it.

It still cannot be tuned. The low speed adjustment do not seem to be making a difference. The high speed does seem to make a little difference but its almost flush out. Temps were around 160. Maybe this old engine needs to be warmed up higher before any changes should be made?

I'm stumped! Its almost ready to go too, new wheels, tires, body, wing, new hardware in a lot of places, new bearings, etc etc. I just want to get this buggy out on the track!

Appreciate any help or suggestions.

 

[Rolex]

The low speed needle only affects idle and takeoff. At about half throttle, the HSN is responsible for WOT. Allow it to warm up, then adjust it accordingly.

 

[dubdeuce]

try factory settings then do not adjust the low speed until the you have properly adjusted the high speed. to keep it running at the factory settings try turning the idle screw in a little 1/4 turn at a time to keep it from stalling at the factory settings. then run it and slowly adjust the high speed needle in until it produces good power but still has good smoke all the way down your straight away at the track you race at. hope this helps. remembe let it warm up before adjusting and after each adjustment run it a lap to let the adjustment to take.

 

[Badsneaker]

I cannot get the engine warm enough. It only got up to 145 tonite. It took so long it was out of fuel. What the hell is the matter with this thing? Its starting to aggravate me now, I've never had this much trouble tuning an engine. This is my 4th nitro, every one has been a different model. I had all those tuned in an hour.

It starts up easily, idle OK. There is a an idle surge every minute or so. I'm thinking the engine is getting warm so the idle is fluctuating. But it totally bogs out when you give it the throttle. You have to give small quick bursts to get a good response. It you give it hard throttle, it seems like it loads up so much it almost stalls. Then you have to give a few small bursts of throttle to get it cleared out.

Is something wrong with the engine maybe? Would an air leak cause this? Why won't it heat up to at least 200?

 

[SkyMaxx]

Did you try leaning it out? If that is all the hotter it got, it sounds like it is running waaaayyyy to rich. The bogging out on throttle input also tells me it is too rich. The surges might be air bubbles passing through.

I'd say try leaning it out a bit at a time and see how it goes.

 

[Badsneaker]

The HSN is almost all the way out, LSN almost all the way in. I know its way too rich but I can't get it running lean enough.

 

[SkyMaxx]

When you say the HSN is almost all the way out...are you saying you have it turned counterclockwise almost all the way? If so, then you have set your HSN to the richest condition it can have...at least that is been my experience...leaning the HSN requires clockwise turns....richening requires counterclockwise. If you have the HSN all the way in...then it is leaned all the way...if you have it all the way out...then you have it full rich.

You might find this link useful in tuning of your engine.

CLICK HERE

Basically...turned in to lean...turned out to richen.

I'd recommend returning the needles to factory presets for that engine...and starting over from scratch.

 

[Badsneaker]

Oh no! My HSN is almost all the way OUT. No wonder it runs like crap. Well so I will go back tonight and start going IN with the HSN. What a moron.

Thanks guys I will let you know tonight.

 

[Badsneaker]

Problems solved pics too

Well the buggy is running like a champ now. I can't believe I was richening the HSN. This sucker really moves now! I am noticing the engine gets loose. Should I use loctite on the engine mounting screws?

Here is 2 pics, when I got it and how it looks now. The new body is being painted. I have replaced the clutch, all the ball bearings, 2 rear axles. I put a new fuel filter along with the splash guard from the MP7.5. I used the Losi fuel clips too. New Kyosho dish wheels on crimefighters with the 17 mm wheels hubs/nuts from the new Kyosho buggies. The MP6 came with 19mm hubs which equals no wheels available. New rear wing, air filter, fuel lines. I also cleaned it up quite a bit.
NEW


OLD

 

[SkyMaxx]

Looks great! Glad you were able to get it running and are happy with it. Now, go out and break it!