I have a 2013 mercury 250 pro xs and having issue with my motor. When it gets to 5500 rpms it's like it dont want to go anymore. Put all new plugs, cleaned all injectors and rail, fuel filter, and tried seafoam. Nothing has helped! No codes on scanner.
Last edited by longdong1218; 01-23-2019 at 01:05 PM.
What boat and prop? What is the best it has ran in this configuration? Have there been any changes since it last ran better? (Im assuming it used to run better than 5500 rpm and that is why you are asking...)
2021 Phoenix 920 Elite / SHO 250
Bullet 21XD / 250 XB (Gone to a great home in LA)
"There is no such thing as a bad day fishing!"
2013 Triton 21 hp. Its ran around 6000 rpm all day long. No changes, just started to notice it wouldnt run no better for some reason and that's why I went to changing stuff!
Perform a compression test according to the sticky at the top of the forum page.
I did one of them and it had 120psi
Test all 6 cylinders following the procedure EXACTLY as it is written in the stickies at the top of the forum page.
We tried that! All tested good
Post results from compression test for each cylinder.Originally Posted by longdong1218
If you have hot foot check throttle cable adjustment
Ok I will
If you would, please review the Forum Announcements and update your thread with the Required Info. Thanks!
Compression Test, Spark Test, and Fuel Quality, Delivery, and Air/Fuel Pressure Tests are all important BASICS that need to be checked.
Throttle cable reaching WOT (as mentioned before) also important.
Prop Information (especially brand, pitch, and ANY damage, no matter how minute you might think it is) is also critically important.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Motor serial# 1B965034
Last edited by longdong1218; 01-23-2019 at 01:06 PM.
Two things:
1. Get engine up to temp and make a 5+ minute run (note- engine must fail to exceed 5500 RPM's as you stated during the 5 minutes).
2. Stop and IMMEDIATELY remove cowling, clip a timing light to each plug wire one at a time while watching for a flashing pattern.
If the above does not reveal one that has no pattern- it will be beneficial to get the Computer Diagnostic System connected and run out on the water for a Cylinder Misfire Test at WOT. Record RPM drop (separately) for each cylinder and share results.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
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