1/2 RPMS

[mjash]

Had the boat out today after a great day last week. WOT would only produce about 2800 rpm. After getting home I inspected plugs. SB cylinders were dry, Port cylinders wet. Also noticed dark oily fuel mix on skeg...tells me not all cylinders were firing and gas was blowing out the exhaust. I am thinking power pack. Any thoughts...is there a way to confirm this?

 

[mikeyzx2]

Re: 1/2 RPMS

could be, hopefully not the goods under the flywheel though(stator, sensor coil and such) as they can me misdiagnosed. you have the exact same motor as me too....make sure you double check your wiring too for breaks or damage

 

[mjash]

Re: 1/2 RPMS

I forgot to mention in my previous post that when I turn key to "off" position it doesnt kill the motor. I have to choke it to kill it. This was also working fine...I am not sure if this is related to my portside spark problem...any help is greatly appreciated. 4am here waiting for sunrise to get this problem fixed. Neighbors are gonna love me.

 

[mjash]

Re: 1/2 RPMS

Just checked compression had between 110 and 120 on all 4 cylinders. Battery was a little low...could this cause my problem?<br /><br />Help is appreciated.

 

[mjash]

Re: 1/2 RPMS

^

 

[mjash]

Re: 1/2 RPMS

Checked for spark tonight at each plug wire all 4 cylinders produced a 1/2" long blue spark of the same intensity. Motor started up relatively easily. Now it shuts down eveytime I turn the key off. This has me a bit confused. Either I had a loose wire that got fixed today with all my fiddleing around or just got a fouled plug that needs replacing...will do that this week. I still have 2 questions:<br /><br />1. What would cause the motor to keep running even after the key is turned off.<br /><br />2. What voltage should be returned to the battery for charging...I am getting right around 13 at idle.

 

[mikeyzx2]

Re: 1/2 RPMS

the ignition switch may be going bad, and I couldn't find an exact figure as far and the charging, I think 13V is fine, 13.5V is normal for car alternators. one thing to check is the amperage the rectifier's producing

 

[mjash]

Re: 1/2 RPMS

Thanks for the reply Mikey, It is a new OEM ignition swithch. And it was awfully perculiar that this was only happening when all these other things were going on. Still has me thinkin that they are all related.

 

[mjash]

Re: 1/2 RPMS

Any other ideas....I am at a loss for why this happened.

 

[CATransplant]

Re: 1/2 RPMS

Mark,<br /><br />I think you inadvertently found the answer. You said that the engine wouldn't shut down with the switch, and ran at 1/2 speed. You fiddled with the wiring, and it all started working OK.<br /><br />Same thing fixed both. I think you had a wire grounding out somewhere. When you fiddled, you moved it so it's not doing that any more.<br /><br />I'd trace all the wires coming from the harness and looks for one with a worn spot in the insulation. That'd be the best candidate.<br /><br />Thing is, your switch shuts the engine down, I believe by grounding a wire. Same wire, I suspect that was already grounded, keeping half your engine from running.

 

[mjash]

Re: 1/2 RPMS

CA....here is what I found yesterday. The power wire from the stator to the rectifier had bare wire.. I checked the diodes and they were good so I re potted the rectifier.<br /><br />Replaced all plugs. Old ones were gapped .025-.030. Started up...ran better than it has since I owned it. River tomorrow. <br /><br />Could this wire have been my problem?