Hit a Log Today

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dwleo

New Member
12 to 15 feet long and about 6" diameter. Couldn't even see it in the Howe Sound chop until it was under me. It hit the stern drives about 12" from the bottom and sheared off the speedometer and transducer. It was a large 'CLUNK' and almost simultaneously the engines went into free wheel. I thought I had lost both props but found I could limp back to Lions Bay marina on just above idle. Got hauled out of the water and both props were fine. Well, one had a ding that can be fixed. Pulled the props to check if the rubber was destroyed. Nope. Just fine. I marked the metal on the inside of the prop so I could see if they were slipping or not. Put the props back on and got launched again. Went out and accellerated on both engines and could not rev past 3600 - 3800 RPM. Tried the engines independantly and each engine was limited to 3800 rpm. Pushed the throttles to the max but 3800 was the top end. Talking with a perplexed mechanic we decided that since both engines are reacting the same, the problem is in a shared resource. But what?

My boat is a 29' Campion and has two 4.3 L Mercruisers and sterndrives.
Any ideas?
 
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dwleo

New Member
Normally - yes. But two inependant distributors and dual fuel inputs and pumps make this a bit of a stretch. But thanks anyways.
 
Sean

Sean

Well-Known Member
Sorry to hear the bad luck.

That is very difficult to diagnose....
I'd probably sit in the boat with a beer (or two) and stare at everything until I saw something out of place....

maybe look to see if you have kinked the control cables...?
 
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dwleo

New Member
Went out to the boat today and the mechanic gave me one prop to put on one engine (put it on starboard) and told me to take it out and go through the trials again. He said once out on the water with the engines running, attach a line from the positive side of the port engine coil to the positive side of the battery. This I did and running only the starboard engine (new prop) - no difference. Running only the port side (new wire) no difference. However, running both together made the port engine blow right past the 3800 rpm barrier but the starboard still was 3800 bound. This tells me that the port engine got a boost from the starboard engine which enabled it to run right up to 4400 rpm with throttle to spare. But how? The hit must have jarred something wonky. Also checked my grounds and will add new temp ground lines from battery to engines and see if that helps

Nothing more fun than trying to sort out an electrical problem.
 
Sean

Sean

Well-Known Member
Well, at least you have narrowed it down to something ignition related. Time for test lights, multimeters and a thick proceedure book. I hate electrical gremlins as they can be so hard to find (sometimes intermittent) and time consuming....which also means wallet consuming.

Best of luck. and let us know what you found.
 
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