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Engine slowing down at higher speeds

D

djadds

New member
I have what I believe to be an engine with a recurring 'limp mode' condition.
After replacing the plugs, impeller, fuel filter and other maintenance items, the problem went away for several outings on the boat. Then, it happened again last weekend, while going across the lake. I arrived at my destination across the lake, stayed for a few hours, then returned back, resuming higher speeds for a significant duration, without a hitch. It doesn't sound like the impeller failing, defaulting to the limp mode on a consistent basis. Any ideas???
 
I am no expert by any means but I am currently working on an 02 125, and I don't believe those motors have a 'limp home' mode. Good luck, I know I am struggling with mine
 
Yes, no limp mode.

Could also be an ignition issue, but try the fuel trick first. A fuel pump rebuild is 1/10th the cost of most of the ignition parts...

But if you are simply looking for a list, my "guess" would be a bad stator. Specifically an issue with the high speed bobbins (which are integral to the whole stator)...
 
galamb said:
Yes, no limp mode.

Could also be an ignition issue, but try the fuel trick first. A fuel pump rebuild is 1/10th the cost of most of the ignition parts...

But if you are simply looking for a list, my "guess" would be a bad stator. Specifically an issue with the high speed bobbins (which are integral to the whole stator)...
Click to expand...

OK, I'm not that astute when it comes to outboard motors, though I have noticed that they should be fairly easy to work on. I'm fairly comfortable with DIY if I'm competent to do it. I've done some minor maintenance work to date.

Are there videos or some sort of diagnostic guidelines that will allow me to trouble-shoot/repair/replace:
--fuel pump
--stator (whatever/wherever that is-sounds like some part of an electric motor!)

I have to keep in mind that this a 13 year-old motor and that a number of items may need repairing/replacing.
It would be good to know if it's better to replace vs repair an item that may require 3+ hrs of restorative work to save $20. I'd like to spend more time enjoying the boat!

Any help would be greatly appreciated!

Thanks, Dan
 
YOUTUBE is full of good...some not so good...videos on "how to" for just about anything. The stator is under the flywheel.

Search YOUTUBE for "mercury OB fuel pump rebuild" and "testing Mercury OB stator".
 
Definitely do the squeeze bulb test first. That will tell us if there is a fuel delivery problem.

It's easy and almost free...no need to spend a bunch of time on youtube(yet)...that won't diagnose the problem.
 
OK, I'll be squeezing the bulb later today. If that 'fixes' the problem, then we know it's a fuel delivery problem. Where do we go from there? Replace the fuel pump?

If so, where do I get the pump and where do I get the info to replace it?

If squeezing the bulb doesn't 'fix' the problem, what direction would I take???

BTW, what does the stator do?

Thanks, gentlemen!!
 
You can get a new pump or kit from this site.\
Open the fuel tank cap to see if the vent is not working.
The stator is an alternator that powers the ignition, lighting and charges the battery.
 
OK, some new discoveries:

Yesterday, we headed out to the lake and we noticed that the line that leads to the 'black bulb' (the one we use to 'prime the pump'), was missing the clamp (a zip tie or any kind of fastener) that would provide a positive seal for fuel delivery, was gone!

So-----I put a few zip ties on it, provisionally, to get us through the evening, and it worked!

This morning I put a hose clamp on it to hopefully resolve the problem.

Now, I might need some expertise to help my thinking with the following:
If the fuel line was not tight, when I get to higher speeds, the fuel pump is drawing more air, and my fuel delivery is lacking, therefore less fuel/more air from the leak, leading to reduced speed on the high end.

In the interest in making things simple, does this sound plausible???
 
If the problem reoccurs it likely a CDM module failing as these like to come and go. It could be a stator but the CDM stators when they fail are usually kaput and a stator will not effect a individual cylinder/s
 
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