[mwinchel]

Hey everyone i have a 1971 1150 engine that i have not had to much trouble out of and i have never been stranded until this weekend. Last weekend my boat run fine all day then this Sunday i put it in the water it cranked up a little funny. I rod away from the dock let it run for a min and then went back to the dock to pick up my buddies. When i drove it back in it cut off at the dock after they were on it cranked back and and we proceeded out of the no wake zone. I went to give it more gas and it bogged down and cut off we went threw this for 10 min or so and then it got to the point where it would not even crank. I messed with it and 1 hour later i got it to crank for a sec and we went 20 feet and it did the same thing. We then had to get towed in to the dock and put it on the trailer. Oh yea i did check spark one 2 plugs and we had spark. I have not changed the plugs for 1.5 years or so but the wires are new. I was told by some friends that it could be my COIL and i will still have spark at the wires but not enough spark what do u guys think.

[Yepblaze]

You lost me when you said it didn't crank yet you were moving.

For most of us to crank the motor is with the key turned and the starter cranking the motor over like a crank on a model T.

Once started it is running but not still cranking.

Even if it's running poorly it still fired off, or fired up, but it's not cranking.


I'm not quite sure what "check spark one 2 plugs" is but I'll guess you have spark.

Being as this (a 71)should be a Thuunderbolt electronic ignition, they pretty much work or they don't. (with the exception of some Rapair/CDI replacement units)

It's possible that you are experiencing a fuel starvation issue like so many others have fought through.

Or perhaps what with the crumbling wire insulation so common on this vintage of old Mercury Outboards (even up and into the controller and keyswitch) perhaps you have some electrical issue.

You said at some point it wouldn't even crank, does that mean the battery went dead (an issue that might cause the problem you describe) or was that meant to mean it turned over but wouldn't start?

[dtmc78]

Did the tell tale stop shooting water at all. Water is low this time of year, and if it is a sandy bottom, water pump tube could be clogged. Might not of noticed it while attempting to board friends. If the motor is hot it will shut down, wait awhile and she will start up and get you twenty yards or so then die. I know it sounds stupid but it happened to me. I lucked out and did not have any damage other than a bad pump.

[monk-monk]

to help diagnose this theres a few questions that needs to be answered: first and foremost, how good is the battery your using, did it have ample charge? the reason this answer matters so much is the fact that you stated at one point it wouldn't even crank...why did it not crank, was the battery drained from trying to start it so much...or was the battery still charged, did you have to get a jump-start to get it to crank when it wouldn't? look at it like this, if the battery had a good charge and wouldn't crank, then you have an electrical issue...and no its not the coil, the coil provides spark to the plugs and even if it went bad, with a good battery you still should have been able to crank the motor...the coil does not charge the battery...and because of all that you've said, it doesn't sound like a fuel issue either...fuel pressure doesn't stop a motor from cranking...im guessing you have a bad internal wiring harness, these older motors are notorious for that! generally what happens in the case of bad wiring is cross-firing between conductors due to crumbling insulation on the wires! when this occurs the wire strands become superheated and will break-down to the point where they will no longer conduct electrical current...until they cool down, and then they may let some electrical current flow again, until they start shorting-out again, then they breakdown again because of the heat! check that wiring harness!