Rationally Approaching Diagnosis & Repair of a 2006 Optimax 250 XS (SN: 1E001696)

[Winnie]

Hi everyone,

I recently purchased a boat with what I was told was a rebuilt (~400 hours ago) 2008 Mercury Optimax 250 motor mounted to it. I sea trialed the boat and it ran fine and as the hull checked all the boxes I purchased the boat without an inspection from a surveyor, and even though I know better, without a compression test. That's all on me; I know better than to do that. But I digress...

I took it out few times and added gas, the additive "cocktail" (linked here from a different site) and oil along the way. All was fine until I got an injector alarm, at which time I asked the dealer at the marina where I store the boat to check into the alarm and let me know what was causing it. Let me say this now, so it is clear: Despite me asking my lovely lady to pump the best quality non ethanol gas when we filled up, it is possible that this did not happen. We don't have the receipt for the fill up, just pumped $100 (cash) worth into the boat. Again, this is on me, I should have gone to the pump with her and walked her through it. Hindsight kicking in again... Also worthy of note is that I used the oil the previous owner used and recommended - Quicksilver Premium Plus, synthetic blend TC-W3 two stroke oil.

Long story short, the dealer called and asked me to visit them so they could "go over the issues and talk about my options."

I had the manager walk me through their findings some which were surprising, let's start there:

1. The motor is a 2006 Optimax 250 XS (gold block and heads)
2. Both the air intake cover and intake attenuator are completely missing from the motor.
3. There seems to be an oil leak at the top of the motor with some components having a clearly visible surface layer of oil on them
4. The oil leak was attributed to a likely failing compressor
5. The Schrader valves for measuring air pressure and fuel pressure at the fuel rail did not have caps on them, appeared mildly corroded and one seems as if it may be partially stripped
6. Oil injectors 4 and 5 are reported as "bad" (the cause of the alarm(s))
7. Compression on cylinders reported as:

1: 125 psi
2: 95 psi
3: 125 psi
4: 120 psi
5: 120 psi
6: 125 psi

In taking photos after the discussion with the dealer, I have found that the oil injectors on the boat appear to be black, not grey or even blue.

The dealer pointed to a couple of other things, such as a missing fastener for the PCM, other seemingly small things and advised me that due to the condition of the motor, it's unknown history and apparent lack of care (who leaves off the air intake cover and attenuator???) that I should consider repowering with another motor. This is something I did not consider happening this soon and I have not budgeted for a repower of the boat beyond its purchase price and in all honesty, it would be a real financial challenge to do so right now.

I thought about this for a few days and have come to the conclusion that even if I were to purchase another used motor, unless it is new enough that it has a warranty, there is absolutely no guarantee whatsoever that it won't have it's own issues at some point in the (near) future, placing me squarely back where I am now.

I'm mechanically inclined, and have experience with working on motors both two stroke and four stroke in other applications so I have decided that the best way forward is for me to get the boat to the house and logically troubleshoot and diagnose the motor until I can determine whether it can be returned to service for a reasonable sum. My natural disposition is optimism, and I have already found myself shopping for the intake cover and attenuator, and a full set of service parts, not to mention oil injectors (how much??! EACH???!!).

I believe my first task is to perform a compression test to either confirm the numbers from the dealer of establish a new baseline to work from. And herein lies my question:

Given I have two injectors reporting as "bad" and I may or may not have the best quality gas in the tank, how do I get the motor to operating temperature prior to performing the compression test? Do I re-route the gas line to a portable tank containing only the best quality gas? Is the two stroke oil used adequate for the XS racing motor? Do I set up a remote tank containing OPTIMAX/DFI oil? What about those injectors? The last thing I want to do is make the situation worse than it is, so I would really appreciate some guidance on this from those in the know.

Additionally, let's say for a moment that the tests return the same results the dealer reported. All would be in spec except for cylinder 2. Would I be correct in assuming that my next step would be to diagnose and uncover the cause of the compression loss in cylinder 2? Surely this, and the extent/cost of replacing/refurbishing the fuel injection system will be the two biggest determining factors in whether it is cost effective to return the motor to service. If the compressor is bad and needs to be replaced, it's expensive but has a defined cost associated with it.

Finally, it is my intention to not just ask for help from members here, but to provide it where I can. As such, I will document my approaches, with photographs as I am able, to help those that visit after me with similar or related questions. To that end, how should I manage the distribution of the issues outlined above? Is it better for me to maintain a single thread here or create a separate thread for each task, or related tasks. What is the best way to approach this for the members a whole? I appreciate any guidance you can offer at this time. Thank you for your feedback.

Winnie

[gehol]

Not much help but Mercury Racing does not recommend DFI oil. They do recommend premium plus as an approved alternate. Their first choice is their racing oil, expensive and hard to find.
I am guessing that motor requires premium fuel but doubt that is your problem at this point.
I don't know what an oil injector is. If you are talking about the air and fuel injectors well, you need to be setting down when you price those. Frankly, a couple injectors, cleaning the rest of the injectors, new compressor, cleaning fuel rails could easily be $4K+. Might be time to look at a reman powerhead.
Don and some other gurus will be along with some good advice shortly.

[06 SB]

I know what I would do first! Hook up the boat and drive 9.5 hours to let Don put his hands on it. He is the man for handling complicated jobs such as yours. He has the ability to service all the injectors in house. I know you say your are mechanically inclined but you are dealing with a thoroughbred that is finely tuned and one hiccup can be catastrophic and costly.

[Winnie]

Frankly, a couple injectors, cleaning the rest of the injectors, new compressor, cleaning fuel rails could easily be $4K+. Might be time to look at a reman powerhead.

Hi gehol, thanks for your feedback. Your points are well taken. I've come to a similar conclusion. I started looking for alternative power for this motor and my options range from dropping a used but checked out OX66 250 on the back with what I have in partial trade to repowering with a 2017 Evinrude 300 G2 with a couple of years warranty remaining. Every option I look at comes with its pros and cons. I have not been able to find a dressed reman powerhead for this motor and the non-dressed offerings would still leave me with my existing issues (except for compression, which would quickly re-emerge without addressing the existing issue(s) upstream. And herein lies my point:

Whatever I "invest" in this motor to get it running as expected will be known good to me. Compressor, fuels system, etc. If I spend money on it I know it is at least up to spec and performing as expected. Sure, I can get another 250 or 300 somewhere else, but there's no guarantee I won't run into the same issues or other issues with it costing another few grand (then another..., you know how it goes). For now at least, I think I have to take a look at what I have logically and rationally and determine whether or not it makes sense to repair what I have or repower.

FWIW, the boat I purchased is a mid 90s 24 foot sea Ray Laguna center console. It's solid, but won't win any contests. I'm not looking to impress anyone, win any contests, tournaments, or trophies. I'd just like to have the boat get me out and back dependably. In hindsight, I got more than I wanted/needed in terms of the powerplant on the boat. I'd like to have a run at getting it working properly if it makes fiscal sense to do so.

[Winnie]

I know what I would do first! Hook up the boat and drive 9.5 hours to let Don put his hands on it. He is the man for handling complicated jobs such as yours. He has the ability to service all the injectors in house. I know you say your are mechanically inclined but you are dealing with a thoroughbred that is finely tuned and one hiccup can be catastrophic and costly.

Thanks for the reply 06 SB. I appreciate what you are saying and I'm pretty sure Don and I will be (well) known to each other soon, but trailering the boat to Greenville is not an option for me. I'm no master mechanic and don't want to imply I am any more capable than I am in reality. I have a decent set of tools and know how to use most of them. I used to restore European sports cars back in the day (Porsches, Jags, etc.) and this situation reminds me a little of a Lotus Esprit Turbo I picked up years ago. Back then, getting 264 HP out of a 2.2 liter four banger was quite the accomplishment and called for squeezing (no pun intended) the most from off the shelf components and working with some very tight tolerances. I'm not sure how the tolerances in the XS compare, but I'm okay at least conceptually with working on the the XS motor.

[gehol]

Might at least give Don and a couple others a chance to think it over. Never know what rabbits they may can pull out of their hat. Might be some sources they know about on a dressed powerhead. Best of luck!

[JOE54]

first of all you should be able to put enough heat in mtr todo comp test on fuel in tank at idle second those blackdirect injectors shouldnt be in that mtr at all they should be gray/ oil on it comes though front of mtr/ may can find a good used late model comp, if indeed its low on no 2= pull head and it is my unstanding (because i have 3 of those mtrs blown right now ) that the pistons are diff from pxs and are not offered over size gotta resleeve if ya gonna redo it ya gotta start with powerhead ,bet oil pump leaks too good luck sir

[JOE54]

ps; dont mix oil with gas in seperate tank more than 4 oz per 5 gal

[EuropeanAM]

A couple of notes:

1. There are no "oil injectors" on this engine. There are FUEL injectors, Direct Injectors, an Oil Pump and Oil Lines.

2. I concur that a properly performed COMPRESSION TEST of your own (see FAQ Section) would be a good starting point.

3. Injectors cannot "report as bad". They would have to be physically tested (individually) to determine that. The PCM has a fault for an OPEN CIRCUIT and a fault for a SHORT CIRCUIT. Neither of these faults is a guarantee that the injector itself is bad (as a wiring or connector problem could be the culprit in either case).

Get some photos of what you're working with and post them... those (combined with information from the compression test and possibly some further inspections) will be helpful in making suggestions.

[gehol]

Winnie, just to emphasize what Joe said about oil. Lubricating oil is NOT delivered with the gas on this engine. The fuel is injected directly on top of the piston. Lubricating oil goes through the crankcase with the air like any two stroke. Running on remote gas tank is OK but, oil must be provided via the stock system to lubricate compressor and the motor.

[EuropeanAM]

Winnie, just to emphasize what Joe said about oil. Lubricating oil is NOT delivered with the gas on this engine. The fuel is injected directly on top of the piston. Lubricating oil goes through the crankcase with the air like any two stroke. Running on remote gas tank is OK but, oil must be provided via the stock system to lubricate compressor and the motor.

^^^^ Pay close attention to this (and Joe54's comments above).

[Winnie]

Hi everyone,

I finally was able to get the boat to the house and perform the compression test as outlined here: http://www.bbcboards.net/showthread.php?t=267446

The compression values I recorded are different to those reported by the shop. I am posting the values with the cylinder number as indicated on the wiring harness in close proximity to the fuel rail, essentially as follows:

Cylinder 2: 112 PSI Cylinder 1: 85 PSI
Cylinder 4: 107 PSI Cylinder 3: 105 PSI
Cylinder 6: 104 PSI Cylinder 5: 105 PSI

What would be my next logical step(s)?

Should I swap a direct injector from cylinder 3 or 5 with cylinder 1 and check compression again?

Should I attempt to view the inside or cylinder 1 with a borescope? I purchased a device I hoped will work for this application.

Should I run a leak down test on cylinder 1? Again, I purchased a leak down tool for this application and would appreciate a solid reference to the best way to do this as I have seen several methods discussed on the interwebs, some putting your teeth at risk... If I go the leak down path I will need a way to lock the flywheel I think. Any suggestions on what tool I can use for this?

Should I look at the reed valve assemblies?

As an aside, I removed the lower cowl halves to improve access to the plugs in 5 and 6 and discovered a large bolt (pic added) toward the front of the cowl which later prompted a quick search for the correct location of the bolt when I located a second, identical bold sitting atop the motor, just behind the intake. I discovered two holes where these bolts appear to fit and it seems that at least one such location is stripped of its thread in the block (pic added). The pic shows one bold mounted (but not fully catching) in the block and the other hole is empty. To be clear, when I performed the compression test, both bolts were not mounted in the block. I'm not entirely certain what symptoms such a condition might manifest, but I'm sure it can't be good. Here again, your feedback would be greatly appreciated. Thank you.


BlockBolt.jpg

BlockBoltMouuntingLocation.jpg

[JOE54]

further inspection is useless must be torn down to repair stripped holes in block half

[Winnie]

further inspection is useless must be torn down to repair stripped holes in block half

I appreciate the candor, Joe. I thought that might be the case (no pun intended).

[EuropeanAM]

+1 to Joe's assessment. If those threads are stripped, you shouldn't spin the crank again until the stripped threads have been addressed properly.

[Winnie]

+1 to Joe's assessment. If those threads are stripped, you shouldn't spin the crank again until the stripped threads have been addressed properly.

Understood and appreciated Don. Thanks for the follow up.

Splitting the case (even pulling the power head) is beyond what I am able to do at the house due to neighbors and restrictions so I have to get the boat in the hands of someone who can go through it.

I'll update here as progress is made in the hope that it will help others.

[EuropeanAM]

That will be an interesting one as it is not a common situation.

[NORRIS CRAFT 1]

Plus #1 on taking it to Don. You could have gearcase problems if it was that poorly taken care of. He is the best their is on Planet Earth.

[greauxpete]

I had a somewhat similar issue:

http://www.bbcboards.net/showthread.php?t=1009859

That being said, you have multiple potential issues with your: injectors, compression and crankcase.

If it's worth salvaging, bringing it to Don will save you in the long run.