Cylinder down on ProXS 175

[thehick176]

Hey guys, I went out last Wednesday for awhile and my motor ran great to my first spot. Fished for awhile and fired up to head to another spot and noticed the motor didn't sound just right. I hit the throttle and it would never get on plane. Last time this happened a few years ago it was a coil, no big deal. I was doing some checking and found the #6 cylinder was dead. I checked it by unplugging each cylinder while it was running and listening for a change. I swapped that coil with another one and #6 was still the culprit.
My next step is to check the plugs because it has been awhile since they were changed. Do you guys have any other recommendations?
Thanks.

[Texas_Rig]

Just do a compression check. You will know for a fact. In my opinion if it was just one cylinder down then your boat would still plane out. Might take a little longer but it should get on plane. I had the same problem when I spun the hub in my prop just recently. Sounded funny and was taking for ever to plane out.

[luckystratos]

I would start with compression check.

[luckystratos]

Texas u beat me by one minute. Lol. If compression is good could be fuel issue to that cylinder. I am not on up and up on merc motors. Do you have a spark tester ?

[thehick176]

Im going to grab one today while I'm out. Hopefully it's nothing major

[tkwalker]

Originally Posted by thehick176

Im going to grab one today while I'm out. Hopefully it's nothing major

Hick, use a known good spark plug. insert in the spark plug boot and ground the metal surface of the plug body against the engine block. (bare surface with no paint) If the motor uses a surface fire plugs you will have to space the electrode relatively close to the block. if it uses a gap type plug it should fire as long as it is grounded... You can use a jumper wire with alligator/croc clamps and connect the plug body to the engine block if you have one. Make sure you use insulated pliers to hold the boot..... I would also recommend pulling the other plug wires so the motor won't start, and make sure to mark them ... <'TK><

[thehick176]

Ok thanks TK. I'll give it a shot

[thehick176]

Just pulled the spark plug on that cylinder and it's burnt up pretty good. Where is a good place to buy new ones?

[luckystratos]

Should be able to get at most parts houses if they are willing to look part number up. They may have to order. Usually next day. Be sure put in factory plugs. Any way you can give us serial number

[luckystratos]

From what I read. Plugs should be
Ngk-1ZFR6J. Gapped at .032-.033 2006 and prior
.042-.044 2007 and later. Better idle
I am not seeing plugs listed at parts houses

[tkwalker]

Originally Posted by thehick176

Just pulled the spark plug on that cylinder and it's burnt up pretty good. Where is a good place to buy new ones?

Hick, how do you know it is burn't ... Compare it to one of the cylinders that is firing ... And then substitute it with the bad cylinder and see if it is firing as per my post ...

From reading your post and thread, I think you need to take your rig to a qualified mechanic before you cost yourself a lot of $$ by troubling shooting it yourself ... <'TK><

[thehick176]

I'm going to change the plugs tomorrow and see if that's the problem, if not I'll take it down to Bobby's at Lakeshore.

[thehick176]

Update: I did a compression check this evening and all cylinders were good. I swapped the suspect plug with another cylinder and the problem followed it. Ordering new plugs in the morning.