Losi DBXL Engine Issues

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TOoSmOotH

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So I got a good deal on a DBXL that is practically new. The guy had a hard time tuning it and kept telling me it "is running rich". He had some weird 2 cycle oil that he got from his LHS. Basically here is the deal. When I put it at the default needle settings it will idle but when I give it gas it shuts down. If I keep leaning the HS needle it will start to REV up but not move forward. So I have to lean it where it is basically 3/4 a turn out from closed give or take a pinch. Once I do that it runs pretty good. If what the dude told me is true he put 2 tanks through it and I burned the third of his mixture. I got tons of oil coming out of the exhaust when I was using his mixture. I now have 25/1 like the manual states in it and it runs good but I am afraid I am going to do some damage with it so lean. I have the low speed needle about 1/16th in from the default.

Am I going to ruin this motor if I run it this lean. Otherwise it never revs up into higher RPMs.

Thanks

Smooth out
 

srusinek

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You might have a defective carb because most carbs are set at a certain point and then you have about an 8th of a turn to work with until you've reached the absolute leanest setting. 3/4 of a turn out sounds way too lean and could cause damage. I would send the motor into Losi so they can diagnose the engine and go from there. Good luck and keep us posted.
 

TOoSmOotH

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So I just got off the phone with Losi and they said that a lot of these engines are running rich from the factory and that it is ok to lean it out that far as long as the temps are within spec. They also said it shouldn't be throwing fuel out like it is so its obviously rich at or near the defaults. So I will lean it and see what happens to the temps.. If they are good looks like that is just what my settings need to be.
 

srusinek

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If you're ok with those settings the best advice I can give is after your next tank I would pull the spark plug and look at it. That would give you the best diagnosis of what's going on inside that engine. For your convenience I attached a link for how a spark plug should look:

http://hpibajass.com/spark-plug-color/
 

TOoSmOotH

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Yea it looks like #1. I pulled it earlier today. I am going to replace it before I run it some more. I also have some new air filters on order as well. I ran it for about 5 minutes and I was in the 170 range as far as engine temps are concerned. Thanks for the link. I'll see how it does with a new plug.
 

HudacksRC

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I purchased a Losi DBXL for my son for Christmas and had the same exact issue. and finally found the root cause is the air cleaner from the factory is way over oiled and it is also to big/thick so when it is compressed by the air filter assembly it closes up the small cells of the foam ristricting the air flow further compounding the over oiled issue. I replace the stock filter with an after market one that fit and oiled it properly. Then put the carb back to factory settings and then hang on it was like a whole new RC. I was then able to tune the carb with ease and it now runs Great! I use the turtle racing air box and clamp on filter. That way you can use a HPI Baja filter which most large scale guys will say is the best filter out there. There are other filter set ups that will work that are not as expensive as well.
Hope this helps
 

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