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Discussion Starter #1 (Edited)
2015 Ace 570. 284 hours. All stock with exception of UNI filter. Putting along engine begins to backfire and loose power..no engine codes showing in dash. Temperature reads 195-ish. BUT engine/exhaust is extremely hot compared to my second Ace 570 (nearly identical hours)... voltage reads @14V 2000rpms... I siphoned out all the fuel and replaced it . Removed thermostat and tested in boiling water...worked just fine...plug changed as well... Ace continues to run poorly, backfire and will stall out..

Any help fellows Acers would be appreciated


Thanks
 

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Mine started to backfire and lose power just like yours before the voltage regulator finally gave out, new voltage regulator and problem was solved
 

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Yes, the ole voltage regulator issue. Berzerker - have a look on this thread about that particular saga? Many of us have either relocated it and/or brought an aftermarket one. It gets caked in mud in its original location and overheats. Good luck.
 

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Discussion Starter #6
I replaced the VR in both Aces since new. Voltage reads @14+volts ant @2000rpms.... How does a faulty VR cause excessive engine heat, backfiring and loss of power?
 

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As a sidenote, the VR is not caked with mud..and should that be the issue causing the Ace to run like sh*t,it will be relocated. In the past, the Aces would eat batteries, I then installed volt meters and as the VR was failing , I would get a engine light and the volts would drop to 12.
 

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I replaced the VR in both Aces since new. Voltage reads @14+volts ant @2000rpms.... How does a faulty VR cause excessive engine heat, backfiring and loss of power?
I have no answer that I can think of for the excessive engine heat but a faulty VR will definitely cause backfiring and loss of power. Most often excessive engine heat or a hot pipe is a lean condition.
 

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Putting along engine begins to backfire and loose power..no engine codes showing in dash. Temperature reads 195-ish. BUT engine/exhaust is extremely hot compared to my second Ace 570
Do you reckon a faulty FUEL PUMP might cause a lean condition?
Geez, I wonder why no one thought of that?
And right before the fuel pressure drops too low to run you get...loss of power and backfiring.
I guess I must be typing in invisible ink.
 

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How about valve clearances. My 1st Ace acted similar to that and re shimmed valves and problem was gone. Just a thought.
Yes. A rancher that posts on the Ranger forums has several 570's and he has had this problem on one with the exhaust valve clearance closing up which causes it to quit when hot. I don't know about it having the hot exhaust but maybe it does.
The intakes are the usual ones to lose clearance and that causes it to be hard to start when cold.
 

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Discussion Starter #14
You may have been correct RM....stealership tech advised fuel pump works but the regulator is not maintaining consistent fuel pressure..... we shall see if the tech is correct..

Thanks all
 

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Kinda sounds like a timing problem. Back around 1970 I had a car do that. It had nylon covering on the timing gears to keep the noise down and the nylon teeth wore down and it jumped a tooth and it did what you describe. Now days that is all computer controlled. I suspect that is also true with the ACE. You might ask one of the larger dealers or the factory.

In the old days it could also have been points and condenser / capacitor.

Did the old plug look light brown [ correct ] or black?
 

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My experience with uni filters on RZR 800 machines was not good. The filter oil would get sucked into the intake tube and coat the air sensor, which during a day of riding would continually lower the idle speed until it wouldn't idle at all. Spray the sensor with carb cleaner and it was good to go for another day!

Backfires equal lean mixture. Fuel pumps are known to weaken and eventually fail. The symptoms are as you described. Check fuel pressure with a load first. Idle pressure may be fine but under a load the pressure will drop. This could be due to a weak fuel pump or a clogged fuel filter part of the fuel pump assembly.

Voltage regulator affects just about everything on the machine.
 
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