Mystery problem 2008 200 mercury opti

[Lvn2Fish]

Ok I’m kinda at a lose of what to do here . My 2008 optimax 200 hp has an issue . When the motor is under a load either fast idling while in gear or running on pad there a surge or “miss “ in the motor . I can feel it for sure behind the wheel . The problem seems to be worse when the temperature is cold . I took it to the mechanic last year and was told there is nothing wrong or they couldn’t get it to happen while at the shop . This winter it seemed to be worse than the year before . So again I took it to the shop only to be told it’s the smoothest 200 they have seen . Wrench you put a new compressor on the motor a couple years ago . Im really at a lose of what the hell is going on . The mechanic swears nothing is wrong . But I’ve owned a boats long enough to know that something is a miss . The sending unit for the gas gauge is not functioning, so I always just put some gas in when I go ... possibly bad / old gas !? It’s currently still at the shop I told them to drain all the gas and I’ll go from there . Not sure really what to do from this point on . My gut says it’s fuel related but I’m no mechanic. Maybe an injector clogged from the shrapnel from the blown compressor ?! Hopefully you can give me a clue Glenn ? 

[fishinwrench]

Water in the fuel, and/or water in the oil reservoir (very common) will cause that without setting any trouble codes.  So eliminate that first.

A clogged or leaking fuel supply hose, bad primer bulb, or a bad Fuel pickup pump diaphragm can also cause that symptom without setting any fault codes.    

[Lvn2Fish]

9 hours ago, fishinwrench said:

Water in the fuel, and/or water in the oil reservoir (very common) will cause that without setting any trouble codes.  So eliminate that first.

A clogged or leaking fuel supply hose, bad primer bulb, or a bad Fuel pickup pump diaphragm can also cause that symptom without setting any fault codes.    

Thanks for giving me starting point ! I really appreciate all the technical help you give all of us . 

[fishinwrench]

4 hours ago, Lvn2Fish said:

Thanks for giving me starting point ! I really appreciate all the technical help you give all of us . 

Your welcome, but it's only "help" if you follow through.    So how long before you know the condition of the fuel and oil?     Water just sitting within those components will cause permanent damage.      So let's get busy!  😊

[Lvn2Fish]

45 minutes ago, fishinwrench said:

Your welcome, but it's only "help" if you follow through.    So how long before you know the condition of the fuel and oil?     Water just sitting within those components will cause permanent damage.      So let's get busy!  😊

They are draining the fuel at the mechanic since there is about 30 gallons in it probably . They still have the boat . I’ll call tomorrow and have them do the same with the oil res . 

[fishinwrench]

23 minutes ago, Lvn2Fish said:

They are draining the fuel at the mechanic since there is about 30 gallons in it probably . They still have the boat . I’ll call tomorrow and have them do the same with the oil res . 

Very few "Certified Mercury" places will check the oil reservoir (because they don't teach that at the certification centers)  and I'm not 100% sure how or why water gets in there..... but it often does.   Condensation from the pressure hose possibly.   

I have a giant glass pickle jar that I can dump the reservoir into and let it set for 30 minutes to see if water separates and shows up in the bottom.    You can't see it by looking through the milky colored plastic reservoir tank.     

You don't have to waste the oil if there is indeed water in there, just let it set overnight, clean the hoses, the pickup tube & screen,  and the engine mounted reservoir, then siphon the UNCONTAMINATED oil from the top of the jar.   You'll only end up wasting a pint or less of oil......'cause that $#!t is expensive! 😅 

Then repurge the O/I system....and you're good to go again.

[Lvn2Fish]

2 minutes ago, fishinwrench said:

Very few "Certified Mercury" places will check the oil reservoir (because they don't teach that at the certification centers)  and I'm not 100% sure how or why water gets in there..... but it often does.   Condensation from the pressure hose possibly.   

I have a giant glass pickle jar that I can dump the reservoir into and let it set for 30 minutes to see if water separates and shows up in the bottom.    You can't see it by looking through the milky colored plastic reservoir tank.     

You don't have to waste the oil if there is indeed water in there, just let it set overnight, clean the hoses, the pickup tube & screen,  and the engine mounted reservoir, then siphon the UNCONTAMINATED oil from the top of the jar.   You'll only end up wasting a pint or less of oil......'cause that ---- is expensive! 😅

Yeah that oil isn’t cheap !  Really nothing about owning a boat is haha . But dang I love to fish ! I’ll update you on what they say tomorrow . My track record this last year with finding people that actually know what the hell they are doing is terrible! If this doesn’t work then I may have to talk you into coming out of optimax retirement 😂

[Lvn2Fish]

21 hours ago, fishinwrench said:

Your welcome, but it's only "help" if you follow through.    So how long before you know the condition of the fuel and oil?     Water just sitting within those components will cause permanent damage.      So let's get busy!  😊

They tested the gas said no water at all . I told them to drain the oil res. Let it separate and let me know . They didn’t seem to happy about that request but what the hell . If they can’t or won’t do it I’ll get a glass jar and have at this week . 

[fishinwrench]

3 hours ago, Lvn2Fish said:

They tested the gas said no water at all . I told them to drain the oil res. Let it separate and let me know . They didn’t seem to happy about that request but what the hell . If they can’t or won’t do it I’ll get a glass jar and have at this week . 

They probably don't believe there is any water in it, and they may be right.....But it needs to be verified for sure before going any further.   

No need to be cranky about it. 😅.  Pretty simple task, I suppose they'd rather be doing something more difficult?   😂 

Since they are already pissed off, go ahead and have them do a siphon test on the fuel supply line.    If all the above is 100% good.....then slap a new diaphragm and gaskets in the fuel lift pump and go test it. 

[Lvn2Fish]

@fishinwrench well things went from bad to worse today . After getting my clean Bill of health I made it about 3 miles . Engine cuts out a few time and while running about 50 I hear a metal clunky noise turned around and put it back on the trailer . I guess I’m driving to lake of the ozarks this week to take it to Danny Burns . Hopefully it’s not the top half of this darn motor . We shall see . I’m ready to fight someone at the other place that shall not be named yet .