OS .21TM on Revo 3.3 Overheating

I have heard the os motors are very unforgiving unlike the traxxas motors. I have a buddy that has a os motor on his and I remember him telling me they have to be dead on tune there's no happy medium and he had to tune a 1/16 at a time either rich or lean unlike a traxxas motor where you can tune a 1/8 to a 1/4 turn and if you get a traxxas motor close they run great. You may try that and just do very small corrections expecially on the low end. I would put it back to stock settings and make very small adjustments to you hit the perfect tune.

u might have an air leak in the gas tank lid, or maybe a leaky bearing on the motor but its rare that that will happen with os engines.. but if u used the stock revo pipe on it u may have damaged the bearings.. just my 2 cents.. but id check the tank and do like the other guy said and start from factory settings.. os engines are really user forgiving

Every OS I've had was very forgiving on tune... and would hold a tune all day long without deviation and could be ran all day long. I've had 7 or 8 OS engines over the years (OS21RG, OS15CV-RX, OS18CV-RX, OS18TM) and all 4 models were solid performers on tune.

I'd suspect an issue with tune, air leak in the engine, air leak in the fuel system. Did you happen to RTV the engine before using it? May be a good idea to try that now at least. Also, check your cooling head bolts.

Doesn't seem to matter the make/model of an engine. I've always found something not 100% perfect out of the box, loose bolt here/there, pinched gasket, silver powder residue inside the crank case... OS, LRP, TRX, OFNA, ORION... all have had something right out of the box that needed cleanup or attention. I've made it a practice to pull every engine apart, clean it, lube it, seal it before a single drop of fuel is ran through it.

I tried that pipe on an XTM24.7 in my revo. Made it run like crap compared to a real bb side pipe. Ended up giving up and sticking with a side pipe. But mine was a true big block. The trinity seriously robbed power and made it run hot. I also tried the fantom pipe... same problem, little less power. Resonator pipe, ditto. Big block side pipe, ran all day long with solid temps in a livable range.

I also just got this engine and it's giving me a hard time as well. I sealed the engine before it went in the truck and there are no air leaks. I tune it for performance and when I bring it in to check the temp it's around 260-270 and I feel like I'm still on the rich side of the tune.There is a nice trail of blue smoke when it's at 260-270. If I richen it at all there is no performance and a ton of blue smoke. This engine only has about 10 tanks of fuel through it. Running odonnels 20% and lc4 plug THS hard coated pipe. I have started from factory needle setting multiple times yields no results. Broke this engine in Ron Paris method.

danuwells said:

I also just got this engine and it's giving me a hard time as well. I sealed the engine before it went in the truck and there are no air leaks. I tune it for performance and when I bring it in to check the temp it's around 260-270 and I feel like I'm still on the rich side of the tune.There is a nice trail of blue smoke when it's at 260-270. If I richen it at all there is no performance and a ton of blue smoke. This engine only has about 10 tanks of fuel through it. Running odonnels 20% and lc4 plug THS hard coated pipe. I have started from factory needle setting multiple times yields no results. Broke this engine in Ron Paris method.

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Same for me, If I get it lower than 260 it's pig rich and no performance, I'm at around 14 tanks now. The problem also is that if I get it at 260-270 like you it runs really good for one tank but then it starts cutting out because it is too damn hot. I changed air filter for a bigger one, I installed the trinity pipe, I tried several plugs and sealed my engine too.... I think I'm installing a sirio .23 instead.

GTI3071R said:

Same for me, If I get it lower than 260 it's pig rich and no performance, I'm at around 14 tanks now. The problem also is that if I get it at 260-270 like you it runs really good for one tank but then it starts cutting out because it is too damn hot. I changed air filter for a bigger one, I installed the trinity pipe, I tried several plugs and sealed my engine too.... I think I'm installing a sirio .23 instead.

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Mine will run all day at 260-270 i dont have the cutting out problem. I took my glow plug out yesterday and turned the engine over i sill have a pretty tight pinch at the top to the point where it gets stuck at the top. So i prob still need to run a little more fuel I'm just going to run this engine since theres good blue smoke and i know that its being lubricated. Luckly like you i got mine off ebay for cheap =] ps i did find a small air leak on my gas tank lid fixed that and it didnt change anything.

danuwells said:

Mine will run all day at 260-270 i dont have the cutting out problem. I took my glow plug out yesterday and turned the engine over i sill have a pretty tight pinch at the top to the point where it gets stuck at the top. So i prob still need to run a little more fuel I'm just going to run this engine since theres good blue smoke and i know that its being lubricated. Luckly like you i got mine off ebay for cheap =] ps i did find a small air leak on my gas tank lid fixed that and it didnt change anything.

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lol I did the same, turned the engine without the plug and it still gets stuck at tdc so it might still need a few more tanks of run time. I will take it out today and run few more rich tanks of fuel, maybe that is all they need.

I will post back later.