Engine developed a miss

[solaidrider667]

My PCM 6.0 started running rough while out surfing today. It dropped at least 1 cylinder. I will check the basics ie- ohm the coil packs-plug wires and injectors as well as check fuel pressure.
Anyone have anything like this happen to you? The boat has 144 hours and is fresh water cooled. It was running fine---all the vitals are in check as far as oil press,water temp etc.

[mtnsmith]

My dealer, FIC, he's on here usually, has a lot of experience with the 6.0. He has a MP 6 liter in his boat, but has been working on PCM's forever. His number is 727-544-6440, ask for Dom...if he doesn't chime in here before you get a chance to mess with it further. Good luck!

[solaidrider667]

I feel like a fool,,,,,,I had been told by the first owner that the engine in my boat was a PCM 6.0. Today while I was pulling spark plugs to check for any issues(due to it running horrible yesterday) a noticed my exhaust reads, Marine Power. So in a closer inspection of the plastic intake manifold cover it also said"Meets Coast Guard emissions specs-----certified by Marine Power. So now I look closer at the ownser manual and find the warranty card stating the model as "GM Vortec 6.0 375HP"
I deserve a whack upside the head!!!
Is this a good engine? Has anyone had theirs start running poorly after surfing? During my fake a lake session it ran perfect! I know I can only duplicate it running with a "load" at the lake.

[mneal]

I would start with basic tune up, do plugs, water separating fuel filters, etc. I always do that stuff right after I by a used thing, even is previous owner says it has been done recently. It lets you start fresh with zero time on maintenance parts and you go from there. If you are really worried do compression test to out rule something large wrong. (unlikely). I believe you could have dealer pull codes to see if it stores and diagnostics from the miss. The 6.0 is typical GM power plant and nothing bad about it far as I know. The surfing has nothing to do it running poorly, it is EFI and should be happy running at surfing speeds all day long. Like mntsmith, FIC can probably chime in with specifics to that particular engine, I am far from a 6.0 expert.

[da.bell]

Do you have any pictures of your current boat? There was a member on here by Wake Havisu that had the 6L engine and didn't want help with his issues. Long story but would like to know if he sold his boat to you?

If he did, then there is a whole entire thread dedicated to the issue of the 6L engine.

[illiniboarder88]

I'd try the fuel water seperator and/or new gas.

[mtnsmith]

Well, now that you figured out you have the marine power, I'd definitely give Dom a call, that is his engine and he has put a TON of hours on it. Ten minutes of talking to him will probably set you straight. And if you did get wake's old boat, Dom had been working with him and his dealer to get things straight when the guy decided he was done trying to fix it, not sure what the actual outcome was.

[da.bell]

Here is some of the issues that Wake had

http://www.tigeowners.com/forum/showthread.php?t=2067

http://www.tigeowners.com/forum/showthread.php?t=2621

http://www.tigeowners.com/forum/showthread.php?t=5147

http://www.tigeowners.com/forum/showthread.php?t=5014

http://www.tigeowners.com/forum/showthread.php?t=2435

[R&T Babich]

... the model as "GM Vortec 6.0 375HP"
... Is this a good engine? Has anyone had theirs start running poorly after surfing? During my fake a lake session it ran perfect! I know I can only duplicate it running with a "load" at the lake.

Our boat has the "old" Mercruiser MAG MPI GM 350.
It had a cracked plug when we got it and ran smooth enough it didn't seem to be misfiring, but lacked power.
Agree with mneal about running the compression check.
I was doing the compression test when I came across the cracked plug.
With good compression and fuel pressure it's probably electrical.
If the misfire is in one cylinder a computer code might help.
Our Expedition had a misfire and the computer code took me right to the cylinder that had water in the plug boot.
With general misfiring I'd check for water in fuel or distributor/computer control (loose connectors, cracked wires, voltage levels, etc).

[solaidrider667]

Bell, I purchased this boat from the original owner and he is a local Las Vegas resident so I am confident it was not Wakes. I do have PPass and my boat does have an actual cable that operates the throttle. The precurser to the misfire was an 2 hours of surfing @ 2500 RPM's +/-. I am begining to think the engine was running warm(despite 56deg lake water) and vapor lock or perculation(sp) was happening. It seems my temp guage never get above 175(poss malfunctioning guage?)---my coolant overflow tank was almost full after I checked it out at home.**no warning chimes while running poorly**
I will replace my lakewater pump, use my infared temp gun to obsereve water temp and I allready have a message to Dom @ FIC about my issues.
BTW I pulled the plugs and all looked good. Also gonna order fuel filter. For those who mentioned fuel,,,,outing prior to Sunday's we filled tank (only took 9 gallons)added fuel stabil and had 4 hours of trouble free surfing. Then Sunday filled tank(10 gal same station-Shell) and 2 hour in,,, poor running. Fake a lake session last night 30 minutes she ran perfect.
I am wauting for Dom's call. Thanks everyone!!

[evil0ne]

Why not call Matt?

[noworries]

If this engine has a distributor you could be due for a cap and rotor.

[solaidrider667]

I am trying to do known fixes for this motor before I spend $150 an hour at the shop. Matt is a great guy but I would like to use my 20+ years ASE Master Mechanic experience first and it appears the fix may be a fuel line re-route.( I hope) If my efforts fail it will be going to Matt for sure.

[illiniboarder88]

My fuel pump gave me havoc last summer. There is also a pressure regulator. At first I did not have problems until the engine got hot. Then it just went completely out. Have you checked the pressure at the fuel rail?

[solaidrider667]

Gonna bring my fuel pressure tester home tonight, I did'nt notice where the port to check pressure was. Looks like I will need an inline adapter.
I will also pressure test my closed cooling as I have had to add coolant after my first couple of trips out in August.