96 Mariner 9.9 running on one cylinder

[T.J]

Hello all. I have a mariner 9.9m serial number 0G364517 runs on bottom cylinder. Unhook top no change, unhook bottom and it dies. Switched coils around, same result. Got continuity through stator and trigger. Switchbox is over $150. Is there something else to check before shelling out the cash & throwing parts at it? Or is there a more thorough test proceedure. Thanks in advance. T.J

 

[carholme]

Re: 96 Mariner 9.9 running on one cylinder

That s/n comes up as:

MARINER - ( 9.9 H.P. (1996 ))
Serial No: 0G364517 Model No: 7010201ED

Parts List for model 7010201ED:

6/8/SAILMATE 9.9/SAILPOWER 15 H.P. - Mercury, Mercruiser, Force, etc. Parts Lookup

If you have the manual, see the tests under section 2A/B. If not and you would like a copy, send me a PM with an email address and I will forward one.

Gerry

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

Many thanks to Gerry. I got the manual & tested stator, coils, and trigger with an ohm meter, all were within spec. I put a spark tester on the top cylinder and its jumping a 5/8" gap, but it's not sparking consistently. I don't have the proper tool to check the switch box but its looking like that's the culprit. I switched the coils around for good measure & it still ran on the bottom cylinder. It sounds like it wants to run right when I unhook the tank & it runs lean while running out of gas. I can't do a spark check on the bottom cylinder while running, obviously, so I am wondering if the spark I am getting from the top cylinder is normal / sufficient to keep the motor running or if my problem might be somewhere else. It doesn't run where you can hear a difference when the top cylinder gets spark here and there, it runs the same whether the plug boot is on or off. Any and all help is greatly appreciated. Thanks again Gerry, T.J

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

Was just reading another thread & wonder if a bad wire from coil to spark plug could be causing this? Ohmed both wires out and read 0 ohms /dead short. Is there a way to check for corrosion without destroying a perfectly good wire? Thanks T.J

 

[MH Hawker]

Re: 96 Mariner 9.9 running on one cylinder

is the top plug wet or dry, switching coils would eliminate a bad wire, being as the plug wire is molded in. More than likely its the switch box. Test the other components and if their good then you know the answer and if you have a dealer close by take the switch box in for testing.

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

Top plug wet. Wires are seperate from coils. I can not use this wire on the bottom cylinder, as it is too short. Thanks T. J

 

[MH Hawker]

Re: 96 Mariner 9.9 running on one cylinder

yes i know I own the same motor I had a problem with mine last year but it was different, motor wouldn't run over 3000 rpms, then it died completely it has a 2 stage voltage Ignition system and the high stage was out then the low stage died.

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

Mine has a ziptie holding the boot at the coil, I had to undo that & pull the wire out to swap coils so the wire would reach the bottom spark plug or it wouldn't run. I put the long wire from the bottom cylinder on the top coil and plug but it wouldn't run on just that cylinder. Maybe I answered my own question but I'm sure you guys know better than me so I'm asking so I don't end up with a spare parts collection. Thanks MH Hawker I really need the help, T.J

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

Is it possible to have no fuel on the top cylinder? I said wet, but both spark plugs looked the same, which was lightly covered with a clear substance like new oil.

 

[MH Hawker]

Re: 96 Mariner 9.9 running on one cylinder

No I dont think so its a single carb and a single set of reeds

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

Ok. Thank you for your help. I will take the switch box to be tested. I still run my 73 Johnson 25 hp & I won't be running the boat until spring so this will be a winter project. I appreciate everyone's help, thanks T.J

 

[MH Hawker]

Re: 96 Mariner 9.9 running on one cylinder

Have you tested the compression that's the only other thing I can think of.

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

Compression was tested a couple of weeks ago by the previous owner 110, 110. I have documentation from the marine mechanic, but he also wrote spark ok, electrical ok so who knows at this point. The mechanic quoted him to repair the primer bracket for the plasitic choke / idle, which i have fixed and the usual impeller, spark plug, gear oil, carb job. It doesn't appear that he ever tried to start it, the bracket was broken & the plugs weren't even finger tight, which I found out after running it (plugs). I did notice something in looking at the manual though, this calls for a NGK plug and it has champions in it. I did a cross reference and the numbers don't match. I'm wondering if I should be so fortunate as to just need a hotter plug. I'm going to call the mercury dealer when they open to see about getting the switch box tested. Thanks MH Hawker, I really appreciate your help. T.J

 

[MH Hawker]

Re: 96 Mariner 9.9 running on one cylinder

Yes you should be using a set of NGK BP8HS-15

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

The marine service departments around here are swamped and can't get to me for weeks. Some didn't even call me back. So I found a thread here to make a dva (direct voltage adapter) & check the switch box myself. Gonna do it today. Maybe I need a switch box, maybe I just need the right plug, but today I'll get rid of the maybe. Thanks, T.J

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

Went through it with the DVA readings were reasonable considering the low rpms. Went to get the correct plug which no one had, so I checked the gap specs & realized the plugs in it were .030 instead of .060. I figure its prob carboned up. Now my question is besides seafoam and the correct plugs, is there anything else I need to do? Thanks T.J

 

[T.J]

Re: 96 Mariner 9.9 running on one cylinder

Hello to all. I got the motor fixed today.
Symptoms: severely rough idle, no change in rpms with top cylinder plug boot disconnected
Problem: somone put new plugs in without checking and resetting gap; severely carboned cylinders
Solution: set correct gap, decarbed the engine
Cost: one can of seafoam
Many thanks to Gerry and MH Hawker, I would not have been able to troubleshoot without the test values from the manual and the dva thread here on iboats. I really appreciate all the help, and look, no spare parts! Thanks again, T.J

 

[MH Hawker]

Re: 96 Mariner 9.9 running on one cylinder

I also had a lot of problems finding the right plugs, I ended up ordering 12 off of ebay.

Very glad you found the problem, and the people here will suggest a lot of testing instead of throwing parts at things. I found out a long time ago while it takes longer testing is better. Now that you have it sorted out you should be fine. Its sad but when you get a use motor it often takes a bit to get it sorted out some of the things that get done to then is really bad. Its so much simpler to fix things right

I will tell you some times about my present motor. I am on a limited HP lake so I am running a 9.9. It has taken the better part of 2 years to find and fix the hafe *** repair the PO did, In my case their just wasn't any 9.9 around so it was buy what I could find or drop 3000 on a new one