250 ProXS starting issue

[JJolley]

Sorry this is long winded but trying to give the whole picture.

250 ProXS
SN - 1B719767

I purchased this boat in March of 2016, the power head had been replace under warranty and was showing to have 105 hours since replacement.
It's been little better than 2 years now and the motor has run excellently with no issues from it at all. Run ethanol free fuel add Don's cocktail regularly, do not abuse it when running, let it idle for a bit before getting on plane and idle after long runs before shutting off.

That being said, this Mercury started like a car every time out, never had to pump the bulb and has run so well that I haven't done anything to it as far as plugs or anything because I didn't want to mess with the performance.

About two weeks ago when first starting at the lake it fired up as normal but died immediately, this happened twice more before it stayed running and then ran perfect to my spot. Fished about 3.5 hours then went to start and again it started and died twice before running and again ran perfect to my next spot, fished an hour then it started right up.

1 week later again it fired and shut down on the first start of the morning but again ran perfect once it started. This time when I went to move after a couple hours it again started and shut down but when I went to restart it, it would not fire. This went on for three separate tries holding the key over for about 3-5 seconds each time, it was as if the kill switch had been pulled.

On the next try it finally started and ran perfect again to the ramp but did seem slightly sluggish.

Checked everything this morning because I didn't want to take it out and get stuck on the water. Below is a picture of one of the plugs I pulled and was wondering if they all look like this could it be the issue.

I'm concerned and baffled and would appreciate any thoughts and opinions.

[Savage]

I would have pumped the primer bulb BEFORE each starting attempt to be able to discern if you have a fuel delivery problem, or a intermittent spark issue, before laying a wrench on the motor.

[JJolley]

Savage thanks for the response and hind sight I agree 100%, until today I really didn't even know where the bulb was however it was pretty firm with a small bit of softness.

I figured that since the plugs have been in the engine for at least the 30 months I've had the boat it wouldn't hurt to change them anyway.

My next issue is that the boat is a 2009 but according the engine serial number it is a 2006 model, could this come from the factory this way? All the plugs are in similar condition and all are bone dry. What should the plugs be gapped for .032-.033 or .042-.044 since the gapping was changed in the 2007 models?

[lpugh]

Even though savage is correct in his statement and I would have done the same
Looking at those plugs make me think:
Overdue for replacement
Poor fuel quality
Incorrect oil
Lack of quick kleen
Trolling
Or any combination of the above, if so you just may need the fuel injectors serviced as well

[JJolley]

lpugh thanks for the response also,

I would agree with you on the overdue for replacement since I haven't changed them in the 2.5 years I've had the boat and not really sure when they were replaced prior to me owning it. As for your other points the fuel I use is 89 octane ethanol free from my local Wawa which seems to be good, the oil I use is Mercury DFI or Premium Plus, I don't use quick Kleen every tank but it is used every other to every third tank and I do idle quite a bit but I wouldn't think it's excessive.

Any idea of where the plugs should be gapped? I'm told the SN shows the engine is a 2006 but the date code on the ECM is 6/20/08.

[JOE54]

.042-.044 /add Q kleen Qcare and prem plus oil to fuel 1 oz each per 5 gal

[SilverFox579]

Don will tell you pump bulb firm before every engine start.

Spark plug change interval is annually (365 days) or 100hrs whichever comes first - your plugs are long overdue.

Just to clarify, Quickare/Quickleen - 1oz each to 5gals fuel. Premium Plus at 150:1 in fuel (approximately 4.2oz per 5gals). I carry fuel to my boat in 5gal cans so use an even 4oz per 5gals for simplicity sake.

Couple helpful topics from the FAQ at top of forum.

Oil, Battery, Spark Plugs, Fuel and Fuel Additive Recommendations

Recommended Annual Maintenance or Winterization for Optimax Engines

[06 SB]

I'm told the SN shows the engine is a 2006 but the date code on the ECM is 6/20/08.

What does your serial tag on the mid section list as the year it was made?

Here is a picture (not mine):

[JJolley]

Update:

The label on the boat confirms the engine is a 2008, replaced plugs gapped at .043. Took the boat out yesterday prior to start I made sure to pump the bulb, it had very little give. Turned the key and it started right up but died immediately, cycled the key off then back on this time holding down the hot foot just a little and it turned over a couple times then started, stuttered but then cleared up and idled and ran fine to my first stop.

At my first stop I shut the engine down let it sit a couple minutes turned the key and it fired right up. I fished for about 4 hours then went to leave, pumped the bulb which was firm and it repeated the same pattern as the morning. I again had to give a little accelerator for it to stay running.

Once it starts and stays running it runs and idles perfect, I am mechanically inclined but I'm not a marine tech so any help is appreciated.

[JJolley]

Another Update:

I think I may have solved my issue... The Gurus will know better but I replaced my battery.

Looking through the FAQs I saw where the minimun was listed at 800CC, my interstate cranking battery was a 27m with 800CCA. I checked the battery on charge and it showed only 13.2 volts after 2 days and as soon as I unplugged it it would drop to 12.7 after just a 5 minutes.

Put the charger back on and hooked up the hose, unplugged the charger, walked up, turned the key and the motor started immediately.Made me think that by the time I got to the ramp in the mornings which is about an hour +/- away the voltage may have dropped lower and the amps with it.

Bought a new X2 battery 31M with 1150CCA, reconnected the hose and everything turned the key and again it fired right up... hopefully that problem is solved but now I'm wondering if my original Triton PS4 charger will work with the AGM battery because the Interstate was just a normal battery as are my trolling motor batteries.

[Savage]

The Triton Charger will work fine...….maybe just a little longer to fully charge.

[JJolley]

Savage I really do appreciate the information, going to go hook it up now.

I just hope that the battery does solve the issue with starting.

[Savage]

[JJolley]

Well as optimistic as I was the issue is not fixed, took the boat out today and same problem with starting and it actually seems worse... I'm at a loss.

It acts like fuel delivery and normally runs great once it starts but today it started having a studder and was idling rough.

[Savage]

Check both thermostats for debris...….you will need two new gaskets, before inspection.

[low slung cruiser]

Inspect the REEDS

[JJolley]

I am so thankful for all the help I've received but I have two grandsons coming down this weekend and they're expecting Pop-Pop to take them out on the lake so I took the boat to RNF Marine today. I've dealt with Ryan in the past and feel comfortable with him working on my boat, he waited for me to get there after work, took the cowl off and immediately spotted an issue with something then said "this won't take long.

I also got a first hand look at one of the new V8 250R 4 strokes,,, gosh I wish I hadn't seen that thing then of course he started it up for me... almost wish my Opti was blown.... not really but that engine is sweet.

I'll post an update as soon as Ryan gives me a call.

[JJolley]

Picked the boat up and I'm happy to report that it is again starting and running, actually better than before.

What they found over at RNF Marine is a blown tracker diaphragm, an O-ring that was not made for this application and some shotty workmanship.

Here are some pictures:

The tracker had seen better days

Now the unexpected, you can see how the top of the threads are dinged up on this cover.

Here's how the set screw was put in, looks like it had to be installed from the bottom, you can see the exposed blue lock tight holding the screw in... barely

One of the O-rings that were installed, it appears this one was not intended for this application and the mechanic said it had swollen almost completely shut. They were amazed the motor could even run.

A picture of the difference between the two O-rings...


I had all the other normal annual items completed while it was there and even though the water pressure appeared to be holding fairly well one of the gaskets were blown so I don't think it would have lasted much longer. All in all I feel quite lucky that I was never stranded on the water at some point. The idle which I thought was good before is so much better now and the engine performance is really smooth all the way through the rpm range now.

RNF did a great job getting the boat in this past week and getting it out before the arrival of my grandsons who had a wonderful time yesterday,

Thank You Ryan for everything you did to get this done in time for their visit, and to everyone that responded on the thread.