Hi there does any one know what temprature a force 25 engine should run at, cause i cant seem to get it lower than 260, even richening the hsn, seems to still go up in temperature. Anyone got any advice, it is brand new and i am breaking it in. Thank you

On any engine as long as it is between 220 and 280 it is fine. What is the oil content of your fuel as this can play a big part. If it is new I recommend the heat cycle method.

what is a heat cycle

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the idea of the heat cycle method is to run the truck 5 times for 3 minutes each time (while making sure the engine reaches 200F). This is the first step. Once your done that, the second step is to run the truck 3 more times for 5 minutes each run. Once again, getting the engine up to temp. If the engine goes above 200F during the 5min runs, thats fine, just as long as it doesnt go past 250.
This whole time, u should run the engine as rich as possible, just as long as the truck keeps running and you can get it to 200F. If it is too rich at stock settings, you can lean it out a bit. I had to lean my F4.6 about 1/2 on both

Sort of the way I do it but put the piston at BDC each time and let it cool down. I do not go by time but by temperature and once it reaches 210 degrees stop it piston BDC and let it cool down. If I have problems getting the temperature up I wrap the head with aluminum foil

There is no definate answer to "what temp". What one person thinks is the appropriate temp for your engine to be at may be different than yours because of so many variables.
Fuel, plug, air temp, altitude, humidity, gear ratios, etc.... all have influence on how hot or cool an engine runs.

Your engine will never be too hot if you do not tune it too lean (assuming it is getting adequate air to the heat sink). Basicaly put, if you tune your engine so that it does not have any lean symptoms, and you have it tuned for crisp and clean transition, you will not have a lean run (due to tune).

I agree to a point fuelman but there it such a thing as too hot. I do not tune to any certain temp but for performance then I check the temp to see it is in a acceptable range. This is why I listed a range.

46U,
I don't want to sound like a jerk, I just want to explain where I'm coming from.
What causes too hot?, (barring mechanical issues which will show up with or without a temp gun).
When somebody twists the needles in too far for the conditions at hand, because they have not tuned to sight and sound where no lean sag has occured. Thats what causes "too hot"

Let me put it another way....
If there was no temp gun ever invented, we would only know the engine is too hot if we leaned it out to the point of seeing it and hearing it sag or fade when wide open. We would automatically know to richen it up. Just like the airplane and heli flyers. It is about recognizing the symptoms of a good tune vs a lean or rich tune.

With all the experienced (engine tuners) racers, flyers and boaters I know, including myself, not a one has ever needed a device to tell them if he is too hot or not.

If the engine is properly tuned for the conditions at hand, it will not be running too lean and therefore it will not run itself too hot due to tune.

Then we would use the spit test. LOL I personally have been to quite a few fairly big races and I see many using a temp gun. Now I have seen many of the cheap temp guns that where not accurate what so ever. [X(]

all the break in methods are funny to me run it rich a 3 or more tanks then ajust it if it blows up its not broke in good

I think the Force 25 is more or less the same as the Force 26. The Force 26 does run hot. 260F is a delicate tune on the Force engine. It can easily go over 300F. At 325, I could hear detonation (sizzling sound at idle after a high speed run).After much experimenting, the end result was it needed an extra head shim to handle 20% nitro.

I agree 100% with Fuelman's post, however the extra shim wasn't addressed...perhaps this could be one of those "mechanical" issues he mentioned.

It will run cooler with a shorty OS A5 glowplug. Also, the carb should be sealed to the engine block with RTV.

Also, make sure you don't have the HSN set to lean trying to compensate for a rich LSN. Tune the best you can, richen the HSN 1/4 turn, then adjust the LSN for best take off after about a 5 to 10 second wait at idle. Then retune the HSN, and finally set the HSN back at least 1/8 richer for reliable running.

Do all this at about 1/2 tank of fuel, or even 1/4 tank to allow for leaning as the tank empties.

just run 3 tanks rich then lean that thing out and run it dont be scared just do it

Yes Argess, another one of those variables I did not mention, great point. If you need another shim, then you are running too much nitro. That alone can cause you to run erratic or hot, and yes, that would be noticable on a high speed run.
The heat gun is not going to tell you that you need to add or remove a shim for the fuel you are running, only your eyes and ears coupled with learning the engine will tell you that.

How do you think us helicopter guys do it? We can't come in for a pit-stop and flash a temp gun on the head. We judge by listening for bog or sag or the crackle of detonation and make adjustments accordingly. Sometimes we have tuning changes to make and if they don't work, we do plug changes and if it still needs help after that, we have shim or fuel issues to make adjustments with. Not one single change we make was because the temp gun had a reading on it, it is all bysight and sound or intuitive "feel". Changes are made to the tune or otherwise to optimize the running condition of the engine, not the tempreture of the engine.