Hi All!

Ok, odd issue the other day. Was out playing and had made several runs across the lake at speed, 5-7 miles max each way, then went and hung out at a dock for about an hour. While heading back at a cruise of about 4300-4500 rpm, the port motor shut off. No noise, no sputtering, it just turned off. Gauges looked fine.

Stopped and checked, and no spark at the coil. So limped home on one.

Its an MSD 6M-2L ignition box, and after going through the MSD troubleshooting, it looked like a bad box.

So, we replaced the box, fired up the motor, and still no spark? Obviously we thought that was odd, so went back though the MSD procedure again, and with the jumper wire, we got a killer spark. But no spark when turning over the motor.

Long story short, the timing chain was broke. Reasonably new motors, less than 100 hours, and very high quality parts.

Has any one seen a MSD box send out odd signals as it was dying that could cause a chain to break? I can't see how a chain breaking could cause a MSD box to go out. But it seems very unlikely that they would both fail at the same time without being related.

Any one ever heard of anything like this? Any thoughts?

I was in a friends single engine boat when something similar happened. We were cruising at about 50 when it shut off. Didn't make a sound, it was like you shut the key off. When we found no spark, we assumed an ignition problem and got towed in. Turns out there was no spark due to the distributor not turning - the chain was broke. It was due to regular length lifters being used in a big m block. It had some run time on it, but eventually a link bar broke off leading to the chain breaking. It doesn't explain the msd problem, but I would definitely look for another cause of the chain breaking before running it again.

aneway - I saw you PMd me but the pm said nothing

I am not getting my pms for some reason I get a notice but nothing in the mail box

If you have somthing to chat about email me at [email protected]

don't think the ignition issue had anything to do with the timing chain breaking...very weird, pull the engine down, either was some cheap chinese chain(does not matter if it was a brand name or not) or something wrong, ck dist and oil pump closely...Rob

+1 No way the ignition box could cause the chain to break.

Yeah, very weird situation for sure. I could easily see one or the other going out, but both seems odd.

Of course, turning a motor off at about 4300 rpm while still in gear can't be a very smooth shut down, and that's effectively what happened.

Hopefully we'll know more Friday.

Marc, I was replying about your truck that you had pinged me on.

I had the same thing happed to my boat @ 20 hr's of operation..turned out the aleignment pin came out of the front of the cam and got lodged between the chain and gears,blew the chain,blew the timing cover apart and bent all the valves..

just my o2

Are you sure the original box was bad or was the lack of spark due to the distributor not spinning?

That was my first thought.

There are several grades of so called performance chains. I had about 100Hrs on the one that came with my rebuild kit. It had substantal chain stretch but had not broken. There is a reason why some cost $39 and others $159. When I did my Roller Cam upgrade I used a Rollmaster chain from RMbuilder. It was Billet steel with a pre-stretched chain. If a expert on this wants to chime in on this therory please do so. Good luck with your repairs.