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Merc 1997 225 hp EFI?????????????

Jerryjerry05

Jerryjerry05

Outstanding Contributor
Hi Merc.Techs.I have spent a lot of money at the dealer(Vero Beach,Fl.) trying to get this motor fixed.
NO LUCK!!!.
I have 1997 225EFI.Ser# OG362927M
It starts and runs good at low speed. I idle out from the pier and try to give it gas and it loads up and bogs down.
I shut it off and wait 4-5 seconds and re-start and it takes off great.I can run and it stays running until I slow down to an idle and will do the same thing.
The dealer and the traveling Merc tech both looked at it.They came up with the stator was bad. They changed it(with a used one) and said it was cured.NOT!!! I got it home and replaced the stator cause it did the same thing.
The fuel pump is NEW and the whole fuel system has been gone thru twice.
The pressure is at 38-39# at an idle or running.
If I can keep the RPM's up it will run good but when I drop them down I will have to shut it off and restart.
I live in Sebastian,Fl and fish the ocean and sometimes re-starting is not an option.
I don't know what to do now as the mech in Vero has NO IDEA what's wrong.Thanks,J
 
Re: Merc 225EFI?????????????

Did they plug it into a DDT and give it a "read".

A bad MAP sensor could cause the symptoms you are experiencing....
 
Re: Merc 225EFI?????????????

I'm not sure what a DDT machine is and I'm not sure what tests were done.They had it for 6 weeks.The guy is factory trained but I'm not sure he had the right test equipment to test this motor. Thanks for the reply.
I worked as a sterndrive mech at a dealer for years and didn't do many outboards.
Now I live in Fl and almost everything has an outboard.J
 
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Re: Merc 225EFI?????????????

DDT stands for "digital diagnostic terminal" your engine will need to be connected to one to find out whats wrong, if your technician is mercury factory trained he should have already done this
 
Re: Merc 225EFI?????????????

Should have and did can be two very different things.

Before anyone can give you any real advice you need to know EXACTLY what was done, tested, considered etc before anyone can form either an opinion or suggest a course of action.

If Merc had this motor for 6 weeks and couldn't figure it out it will be tough for any of us to make any kind of recommendation without all the facts...
 
Re: Merc 225EFI?????????????

I have a pair of 1997 200 EFI's and had (have) almost the same issue last year. After a lot of troubleshooting I traced it back to a bad trigger. I replaced it and it ran great. Unfortunately now the same problem appeared this past weekend. Does anyone have any ideas as to why the trigger could have gone bad after 3 months of light use? Was the problem consistent with a bad trigger or did I happen to fix the problem temporarily by messing around the wiring?
The tricky part of the troubleshooting is that I flip back and forth as to whether it is a fuel or ignition problem.
 
Re: Merc 225EFI?????????????Problem found!!!REad this!!

Hi , I was in touch with a service tech.He was answering my questions on a 97 Merc 225EFI. It had performance problems.
Well I figured out my problem.The regulator that EVERYONE said NEVER goes bad was bad.The Mercury Tech and the local Merc.dealer and a half dozen other said yea that part never goes bad but it did.
The repair manual said:Check the pressure and if it is between 36-38# it's ok.Anything above that or below replace it.Mine was at 42# but EVERYONE said they never go bad.
My luck!!! I have the only one in the world to go bad.Pass this on.Jerry
 
Re: Merc 225EFI?????????????

I saw that once on a 250 and fooled me too. That is hard to measure. The pumps have a blowoff valve inside them on the EFI motor's. Pinching the return line does not do what you expect it to do. The pressure goes down instead of up.
 
Hello folks, always check your fuel rail pressure Schrader valve before testing the pressure! Clean it well to achieve a more accurate pressure reading. Fuel residue will build up inside the valve especially if you run 87 octane gasoline and possibly not from a reputable fueling station. The Merc 225 EFI was designed to run a minimum of 89 octane (What some call midgrade) which is better than running 87 but, 89 is a mix of 58% 87 and 42% Highgrade which means you are still getting 58% of the dirtiest fuel you can buy! If you are trying to save money buying 89 in the long run you'll probably spend what you saved in engine maintenance. Bite the bullet and run Highgrade fuel at least every 3rd fill up or all the time, if you do you will find you will achieve increased power, increased fuel economy, and less required overall engine maintenance. The other issue is what oil you run in your 2 stroke engine, you want to run synthetic for excellent lubrication and longevity of your engine and it's much better for the environment of the lakes and rivers you enjoy every year. Happy Boating! Jeffrey Thomas, NC.
 
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