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Low powerrpms at full throttle 4 stroke

A

amstaff

New member
"04 50hp 4 str efi
I finally

"04 50hp 4 str efi
I finally got out on the water, first time all year. The motor started up no problem, a bit of rpm bounce from 800-820 at idle/neutral. Got her out in the open and decided to open her up. My problem is she would not go more than 3200rpm. I put fresh gas in this morning-premium. I did have a cross-threaded plug last season, so I brought it to a merc. technician-he removed the head and put in a heli-coil. Thought I'd mention that, may have something to do with it. The rpms did go higher in reverse. Sorry, just putting things down that I remember as they come to me. Any help or ideas would be greatly appreciated.
Thanks in advance"
 
"Sorry, 4 strokes are a "n

"Sorry, 4 strokes are a "new beast" to most of us on this board, they just haven't been around long enough or become prolific enough that most of us can say "ya I've seen that before".

The motor is 4 years old. Has it had "ALL" Merc's specified maintenance when it was due?

Have the valves been adjusted? any belts? oil changed on time including filters? has the motor been "winterized" properly when not in use for more than a few weeks?

You don't go at these with a screwdriver, you need a computer to diagnose issues - TPS? ECM? etc etc - you don't fix parts on these, you replace.

I assume that you have had the motor get above 3200 rpms in the past?

I don't think your issue with the stripped plug has anything to do with this. If it was a two stroke I would suspect a fuel problem, and that well may be the case with this one - except there are so many "more" factors with a 4 stroke and the syptoms can mimic alot of issues.."
 
"Thanks for your response Grah

"Thanks for your response Graham. Prior to stripping the plug it ran beautifully-5500-5800 rpm at wot. I have winterized according to manual, I also changed plugs and fuel filter.
I'm going to take it back to Merc. tech and get him to hook it up to the diagnostic and cross fingers that it's something minor.
I also wanted to know if you or anybody else could recommend a prop repair/sales company located in GTA, Ontario,Canada.

Thanks again"
 
"A great place is just outside

"A great place is just outside of the city (can even purolator back and forth to save the gas).

J and J RR # 3, Hagersville, Ontario N0A 1H0, (905) 768-9188
(where the big tire fire was, if you are old enough to remember)


They have a website - www.jandjmarine.com"
 
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