Pyrometer Reading too High

[Mirage2004]

I have a 2000 model Merc 200 Carb motor on a Mirage Ski Racer and I know that the motor is getting plenty of fuel because I am running an Electric fuel pump, but if I get the motor turning over 5000rpm the pyrometers read 1250 to 1300 degrees. What could be causing the temp to get this high? Could it be my guage? The guage is a Gaffrig. The motor seems to run really strong and has never give me any trouble I just don't like seeing those readings.

[Reaction19]

CHECK THE CARBS AND MAKE SURE YOUR NOT RICH OR LEAN THEY WILL BOTH GIVE YOU A HOT READING. ALSO TALK TO JAY@SSTMARINE HE KNOWS THOSE CARB MOTORS REALLY WELL EVRYTHING HE HAS TOLD ME TO DO HAS WORKED LIKE HE SAID AND HE MAKES ALOT OF STUFF FOR THOSE ENGINES. HIS NAME ON THIS SITE IS MARINERRACING.

[Jay Smith]

Mirage 2004,

Sometimes an EGT reading is mis leading and not reading exhaust gas temperatures at all and is reading flame. This can occur when the motor is way to rich and the motor is not getting complete combustion. When this occurs raw fuel can creep out the exhaust port and then ignite causing the probes to "see" and show a hotter lean condition and really be quite rich.


I might suggest making a hard pass and killing the motor as clean as saftley possible then look at #5 bore at bottom dead center. Look on the intake side of the piston ( toward the outer side of the block ) and observe the "wettness" out from the intake ports toward the center of the crown. Most motors are safe with that area being wet the size of a nickle and the crown with a chocklate color. Any less I would jet up. An ashy color would mean the need for a jet change at that observation point BEFORE the next high RPM pass.....

Also check your probes they can "coke up" with carbon become insulated and give a false reading too........

Good luck !

[Liqui-Fly]

The fact that you're running an electric fuel pump does not, or atleast should not, effect whether or not your motor is running rich.

[us1]

Jay is right, an EGT is just a monitoring tool. You really should be reading the pistons and them monitoring the motor with the gauge for any changes indicating a problem.

[gonefishing_68]

I'm running a 04 xr6 that read 1375-1400 bone stock. I thought something must be wrong so I put the gauge on a stock 200 efi and it read 1375-1400. So I said it's got to be a bad gauge and sent it back to be check out. lavroski siad it was right on the money. Well needless to say both motors are still running hard every week. My motors plugs are tan to dark brown and you can see some wetnesson the intake side of the piston. Pyro's are just a gauge and nothing in stone.

[Jay Smith]

Gonefishing_68


If your EGT were truely at 1400 degrees you would have 6 piles of gue where your pistons were..........I suspect a calibration problem. I also would not believe everything a vendor told me either.

Good luck,

[us1]

Gonefishing_68


If your EGT were truely at 1400 degrees you would have 6 piles of gue where your pistons were..........I suspect a calibration problem. I also would not believe everything a vendor told me either.

Good luck,

How true it is.

[gonefishing_68]

I thought it was the gauge or probes also but Livorsi said it all checked out good. Who less checks these things?