Mercury 225 efi not plaining

[duskydiver]

Hello all,

I was wondering if anyone can provide some feedback on this problem I've been having. I have an 84 Dusky 23.3 CC with a 98 Mercury 225 EFI. I recently replaced the lower unit which came about because the boat was having issues plaining. First I was told it was due to the pitch size of the propeller I was using which was a 17. Then after testing both a 21 and a 15 with no results. I was asked to check the oil in the lower unit. To my surprise what came out was greyish mud. I was then told the lower unit was bad and had a mixture of water and metal which was easier to replace than rebuild. So, the lower unit was replaced. Next came the water test with no mechanic which was busy at the time. Same thing the boat would not go into plain and at full throttle it stayed at 2200RPMs. I was then told by two other mechanics one that it was the stator, and the other that again it was the pitch size. Has anyone gone through this issue.

 

[starcraft1982]

Re: Mercury 225 efi not plaining

i would suspect that youre missing 1 or more cylinders while running.i would first pull plug wires off,one at a time,while idling,listening for the change that should be there.when you get to one that doesnt sound like it changes the motor running,swap a coil from a good cyl. to that one and re test.if the prob. moves w/the coil to other cylinder,theres your prob.If none found,then youll need to start digging more.ALL THIS SHOULD BE DONE AFTER YOU CHECK COMPRESSION.NO USE THROWING MONEY ON A BLOWN MOTOR!it could be other things.just tring to start you somewhere.my cousins 250 proxs did same thing.idled fine,but when you throttled up,wouldnt go past @3000rpms and just no power.it was a coil.get back w/results.

 

[duskydiver]

Re: Mercury 225 efi not plaining

Thanks for the reply starcraft. I had the cylinders checked for compression and all cylinders were at 100 compression. Also, had a coil replaced before all this mishap. I'll check them again as you stated by unpluging wire from spark plug one by one. I'll get back with the results.

 

[duskydiver]

Re: Mercury 225 efi not plaining

I was able to pull the plug cables individually while the engine was idling. I did notice on one of the coils when pulling the cable I was getting shocked quite a bit. After pulling the cable the engine did a small sputter. None of the other cables caused this shock nor the sputter. Could this be the issue?

 

[duskydiver]

Re: Mercury 225 efi not plaining

Any other ideas on this. Your help is appreciated. Engine still not going past 2200RPM, will not plain with new prop or new coil.

 

[ifixf18s]

Re: Mercury 225 efi not plaining

Not quite sure, but i dont think you can just change the prop to whatever you want, i mean you can but theres advantages and dissadvantages depending on the prop pitch you choose it can effect the RPM of the motor. Could the tilt on the motor effect it? trying to learn here. Or is it stricly an engine performance issue?

 

[SigSaurP229]

Re: Mercury 225 efi not plaining

Maybe a clog in the high speed on the carb.

Could be that the Stator is going bad not throwing a hot enough spark all the way around.

Timing could be off

Check the spark advance (all though i think this problem would be evident upon going into gear).

 

[Faztbullet]

Re: Mercury 225 efi not plaining

You have the 3.0 lite EFI which had several problems, make sure you have had the t-stat updates(SB 2002-8) for one. As to your problem it could be several things and are you getting any warning horns or lights?
Things to check:
1) throttle position sensor
2) short stop diode in CDM causing cylinder/s not to fire
3) cable not opening throttle arm all the way
4) weak fuel pressure(filters & pump)

 

[islandcruiser]

Re: Mercury 225 efi not plaining

You have the 3.0 lite EFI which had several problems, make sure you have had the t-stat updates(SB 2002-8) for one. As to your problem it could be several things and are you getting any warning horns or lights?
Things to check:
1) throttle position sensor
2) short stop diode in CDM causing cylinder/s not to fire
3) cable not opening throttle arm all the way
4) weak fuel pressure(filters & pump)

Ok sorry for asking a question on another post but my post has not recieved any responces and I am having very similar problems. I am awaiting the delivery of my merc manual and have no idea where or what the short stop diode in the cdm is. Could you tell me please? I am very mechanicaly inclined with cars, carbed outboards, and inboards but I am new to efi outboards. Any help would be greatly appreciated.

 

[islandcruiser]

Re: Mercury 225 efi not plaining

I was able to pull the plug cables individually while the engine was idling. I did notice on one of the coils when pulling the cable I was getting shocked quite a bit. After pulling the cable the engine did a small sputter. None of the other cables caused this shock nor the sputter. Could this be the issue?

The sputter indicates that when this coil is hooked up it is working correctly untill it is unhooked despite the shocking. If it is a coil it will be one that makes no difference to the idle when the cable is removed. Correct me if I'm wrong here. Good luck Duskydiver as I am having the same problems with mine with no luck yet. Its a 97 225 efi but they are very similar.

 

[duskydiver]

Re: Mercury 225 efi not plaining

Thanks guys for all your input. The problem was that I didn't notice that the entire right side made no difference when pulling the plugs individually. After testing the current on each cylinder, we noticed that the boat is running on only 3 cylinders. What seems to be bad is my stator. Changing that out and hopefully this will solve my problem. Again thanks for all you input.

 

[islandcruiser]

Re: Mercury 225 efi not plaining

Thanks guys for all your input. The problem was that I didn't notice that the entire right side made no difference when pulling the plugs individually. After testing the current on each cylinder, we noticed that the boat is running on only 3 cylinders. What seems to be bad is my stator. Changing that out and hopefully this will solve my problem. Again thanks for all you input.

Please post your results and let me know how you did. Good luck.

 

[Faztbullet]

Re: Mercury 225 efi not plaining

Check your shift switch as some year models it kills spark to 2,4 & 6 cylinder

 

[duskydiver]

Re: Mercury 225 efi not plaining

Just got the stator delivered, awaiting all this rain to clear so my mech can install it. Let you know of the outcome. Hopefully its the stator faztbullet. I'd hate to keep wasting money on the engine. So far this little incident has cost me 1700 bucks.

 

[jcory]

Re: Mercury 225 efi not plaining

My 95 225 magnum EFI has the same issues--Throttle Position sensor was out of whack and it seems that it wasnt letting out enough exhaust. I have a 23p 4 blade stainless on mine pushing a 20 ft charger. I am going to have to have exhaust ports drilled into my new prop to help get rid of the exhaust and not have a backpressure build up.

 

[islandcruiser]

Re: Mercury 225 efi not plaining

Just got the stator delivered, awaiting all this rain to clear so my mech can install it. Let you know of the outcome. Hopefully its the stator faztbullet. I'd hate to keep wasting money on the engine. So far this little incident has cost me 1700 bucks.

How did the stator work out for you?

 

[duskydiver]

Re: Mercury 225 efi not plaining

Here's what has been done since. Changed the Stator, changed the ECU, Changed the manual fuel pump, got new coil packs, and still nothing. The engine sounds nice, but sputters alittle, and smokes alot. Got to 2700RPM and it just stayed their and never got to a plain. This is getting really frustrating. So far $2300 spent and still nothing. Could it be the throttle cable?

 

[duskydiver]

Re: Mercury 225 efi not plaining

Hey just getting back on this thread. Just so you know the issue was with a lose cable that was causing a short in the engine. It was part of the wiring harness. It kept shorting the 3 cylinders.