Optimax 225hp acts like you switch it off then back on from time to time

[Chopper]

Mercury 2005 225hp Optimax SN: 1B160213 (not an XS model)

Running a 26 Tempest +
Max RPM = ~5500
Idle WP = 2-5 psi, WOT WP = 22-25 psi
Merc monitor installed

My motor is idling rough intermittently and oftentimes when you drop it into gear it acts like you shut the ignition off for a second or maybe two then it comes right back. It seems to do this when it is cold, (if you want to call 70 degree water cold) but the motor is at normal operating temp (125 degrees) when it does it but seems to do it more when it has not been run beyond idle yet. As mentioned, it only does this on occasion, otherwise it runs and idles perfectly.

Would a tracker valve cause this? I have replaced the plugs recently so I'm pretty sure that isn't the cause. I even put the old plugs back in but it still did the same thing. In the past, I have replaced the tracker valve three times and the fuel regulator valve once on this motor. That's why I'm thinking tracker valve. The tracker valve that is in there was replaced about two years ago.

Any suggestions or thoughts??

[EuropeanAM]

That would be one of a number of possibilities. I would recommend starting with the BASICS, and working in a methodical approach:

-Compression Test
-Spark Test
-Fuel Quality, Delivery, and Air/Fuel Pressure Tests *
-REED INSPECTION.

*Record results for idle, under acceleration, and 5/10/15 seconds after engine shutdown. MUST use glycerin dampened, DUAL gauge set.

[Chopper]

Thanks Don. This is the engine that you installed the fiber reeds in a year or so ago, among other things. As far as the other tests are concerned, I do not have the equipment to do all that so I'll probably run it by a dealer and have him take a look at it.

[EuropeanAM]

One other thing to watch for is a sticky or intermittent Shift Position Switch. Can be due to a failing switch, excessive grease on the slide (that's hardened), or even an over-tightened nut at the end of the shift cable (must be snugged, then backed off 3/4-1 turn).

[Chopper]

I guess the issue was caused by the tracker valve. Here is what I found when I took it out.

fast image hosting

Don this is the 5th tracker valve that I have installed since you worked the fuel rails and injectors and etc, a couple years ago. (I do not recall the exact time when this was done) I never had one go bad prior to you doing that work. Could this continuing problem be related to the fuel rails, injectors or what?

The last time it was the air regulator valve in the port rail. That one is expensive to say the least! The closest dealer to me charged me $300.00 to replace the first tracker valve that went out, so I learned how to replace them myself. The last four tracker valves I have had go out, I have installed myself. The tracker valves run from $112.00 to $150.00, depending where you buy them at. That's well over $600.00 in tracker valves that I have had to install in this engine.

I feel like I'm just fixing the symptom and have not addressed the root cause of these tracker valves going bad. Any suggestions as to what is causing this? I really need to stop this bleeding.

[EuropeanAM]

Billy- looks like I saw those rails back in March, 2016 (when you last had your boat here)... so that's a little over 3.5 years ago. Someone had been into the Port Rail and had stripped the bolts for the Fuel Pressure Regulator (enough so that the rail body on that side had to be replaced). No diaphragms were bad or replaced at that time.

There are several items we see as commonalities in repeat diaphragm failures, including (but not necessarily limited to): Repeated engine overspeed conditions (rev limiting), Repeated attempts at accelerating beyond a Guardian Limit, Fuels with too high an Ethanol Content, and in some cases- additives that may not be compatible with the components used in the Optimax fuel system (not getting into brands or names here, but there are some well known off-the-shelf products that are at the least quite suspect).

All that being said... the Tracker Valve is NOT the same as a Fuel Pressure or Air Pressure Diaphram, they are completely different components and are not interchangeable.

There were some diaphragms that had a higher tendency to fail (IMHO) and it appears to have been a vendor problem. NEW Mercury Parts and Accessories carry a 1-Year Parts and Labor Warranty, so if one of these fails as pictured above within 1 year of date of purchase, ANY Mercury Dealer can process a P&A Claim (you simply need your Purchase Receipt from an Authorized Dealer).

Do you have all of your Tracker Valve Receipts?

[Chopper]

Don, No unfortunately I do not have my receipts. Like a dummy I trashed them thinking I would never need them. No the engine has never been on the rev limiter excepting for maybe once or twice since it was new and has never been in guardian mode so there would have been no chance of over rev under that or any other condition. I am aware that the tracker valve and the fuel and air valves/diaphragms are not the same. I've never interchanged those nor would I.

As far as additives are concerned, the only thing this motor has ever had is Quickleen and for a time I was using startron but in the last year or so I have switched to the Mercury product exclusively. I don't know about the Ethanol content but the pump says it does not exceed 10% and I use only regular unleaded gas in the motor and I seldom purchase fuel at the same place twice. Should I start using non ethanol fuel? It's more expensive and is hard to find in the same octane rating as regular gas. (87 i think)

I have no answer for the damage you found in the fuel rail. That motor had never been into and I am the only owner. Right after I bought it, it spun two sleeves and Mercury provided a new power head which was installed by a Merc master tech. Said to be the best Mercury Mechanic in North Florida.

I did not realize it was that long ago that you worked on the motor. Time sure flies don't it? (BTW, I wasn't trying to tie your work to the tracker valve problem, even though it did sound like it when I reread my post. That was not my intent) The issues you mentioned in your post really do not apply as stated above, I haven't exceeded the rev limiter in the past 5 years or so. I did get on it when I first bought the motor once or twice, after breakin, when I was searching for the right prop and PVS hole combination. But that was years ago. The motor has never been in guardian mode, use only mercury products as per your suggestion for additives, and have not tried to use a fuel/air diaphragm for the tracker valve or visa versa. I'm very aware that they are different and not interchangeable.

I'm perplexed as to what could be causing the repeated tracker valve failures. Any other suggestions? (thanks for the help!)

[EuropeanAM]

As long as you remain below 10% ethanol content you should be fine. GOOD move switching to the additives you are using now (no further comment on that).

Given the area that is split on the tracker valve I suspect it is simply a material failure. Can't speak for the others... address the current one and monitor it carefully for any further problems.

Good catch, BTW!