Mariner 200 missing

[elit4ce05]

Hey everyone and thanks for letting me join in on your discussions. Evenyjough I haven't posted here before,these forums and the answers you guys give has been ultr helpful in the past.
Anyway.... I have a Mariner 200. According to the serial number, it's a 1983. It has always ran great, a real hoss. The problem started a while back when I was on a plane it would feel like it lost power briefly,then it would go right back to running fine. When it's running at it's peak, it will turn about 6200 rpm. When it would have it's"problem", 5400 was all I could get.
I suspected broke or loose wire, maybe loosing ground somewhere. Checked everything retightened grounds,things like that and didn't have a problem for quite a while.
Two weeks ago, it came right up out of the water just fine ,then started having it's "problem". This time it hasn't went away.
It appears to be in the #6 cylinder. I only say this because pulling that plug wire makes little to no difference in the running of the motor.
Compression on all cylinders are between 115 and 119 with #6 being at 117.
Replaced stator with known good... same problem
Replaced switch boxes with known good...same problem
Cleaned carbs......same problem
Replaced all coils with known good...same problem
Ordered a DVA to get correct readings,should have it today.
Anyone have any suggestions I could try while I wait on the DVA?

 

[Faztbullet]

Re: Mariner 200 missing

Check trigger spec's and for spark on # 6. Index the flywheel and check timing on # 6. If all is ok pull head and check for scuffing on exhaust side of piston as the chrome bores can show good compression and leak down be out the roof...

 

[elit4ce05]

Re: Mariner 200 missing

Will do...thanks.

 

[elit4ce05]

Re: Mariner 200 missing

checked triger specs...within specs
timing .....check
compression check 117 and holds
inspect cylinder walls ...looks good
All electrical falls within specs and has been replaced with known good. Carbs rebuilt. Still has a miss and won't accelerate over 4000 rpm

 

[jeffersondodson561]

Re: Mariner 200 missing

I would change #6 plug with another plug and see if problem follows plug to another cylinder when you do a cylinder drop test. Turning 6200? Is your tach accurate? Kinda high on the rpm's.

 

[elit4ce05]

Re: Mariner 200 missing

changed plugs. I'm about to pull my hair out with this thing. Everything has checked out as per the manual. It has to be something somewhat unusual. I read on here where the fuel pressure should be 5 to 7 lbs. So I checked FP and it was around 3.5. I rebuilt the fuel pump and still have 3.5 but after checking the manual, that is correct for that engine. Could reeds be a possibility?

 

[elit4ce05]

Re: Mariner 200 missing

I really have no reason to doubt the tach. It usually idles at around 950 to 1000. Right now, it is around 850 to 925.

 

[jeffersondodson561]

Re: Mariner 200 missing

Did you inspect the reeds on #6? I wouldn't worry about the fuel pressure, I would be concerned with a fuel restriction. Have you put a timing light on #6 to see if it is flashing/sparking at rpm?

 

[elit4ce05]

Re: Mariner 200 missing

Yes I have put the timing light on it and it appears fine. I have not inspected the reed at this point. That would be next. Actually it's about the only thing I have not done.

 

[elit4ce05]

Re: Mariner 200 missing

fixed......1 bad reed valve and gasket was shot...replaced ,runs like new...thanks,

 

[Jake_MN]

Re: Mariner 200 missing

Glad to hear it was fixed. Out of curiosity, is the 6200 RPMs the max spec for that engine? Seems a bit higher than the usual 5500 or so.

 

[elit4ce05]

Re: Mariner 200 missing

I know it's turning a little high, I think 5800 is normal. This is my brothers boat and he has made several prop swaps, so that could be the reason for the higher rpms. His is a 1983 mariner, mine is a 1984 mercury. Both are 200s. They appear identical both are 2.4. I have a five blade prop and I turn 5950.