Mercruiser Model 165 (GM Inline 6, 250 CID) Starting problem

[wolfsterman]

Ok, so I have an older Seaflite with a GM Inline 6, 250 CID, and I replaced the points, and condenser tonight, and the motor wouldn't start at all. I know there is spark from the coil, nothing was changed, and it fired right up before I changed the points and condensor. Could the gap be wrong? It's been several years since I messed with points. Please help me here. Thanks in advance.

 

[ziggy]

yes, something changed. ya replaced the points.
i use a dwell meter after replacing my points. dwell for my '75 L6 is 31*-34*. if ya must use a feeler gauge, gap is .022".
also, ya need to check timing after replacing the points. adjusting dwell affects timing.
so, set your points dwell with a dwell meter, then set your timing. again for my year L6. timing is 6* btdc @ idle. be sure it's at idle. centrifugal advance starts pretty fast with increase in rpm. so if it's idling to high you'll set your timing wrong.

 

[wolfsterman]

I can't set the timing until I can get the motor started. I will try readjusting the gap on the points today. If anything I can put the old points back on and maybe just order an HEI conversion kit. Thanks for your help.

 

[Fishermark]

Your new points may have a glaze on them. Try cleaning them with some electronic cleaner spray. Your timing should not be off too much if at all simply by replacing the points. It does need to be checked of course.... but it sounds like you may have either installed the points wrong, or they need cleaned.

 

[wolfsterman]

Ok, so I tried reinstalling the old points, condensor, and cap, as to get me back to the point when it last fired. Nothing. Bought and installed a new coil, still nothing. There is spark at the end of the coil wire, and at the end of the spark plug wires, which tells me that spark is getting through the distributor. Even tried to replace points with an electronic ignition conversion kit, and still no spark. I am getting a little frustrated here. This all started just by simply replacing the points. I am thinking maybe it's the distributor itself? It does have quite a bit of play in the distributor shaft.

 

[ziggy]

since it ran prior to replacing the points. 1st guess as to where the problem is would be with the points.
ya might wanna read 18-19 from this link. it may be helpful

 

[Fishermark]

You mention it has spark. How are you testing that? If you are correct about it having spark, then some other issue is the cause instead of the ignition.

 

[wolfsterman]

Thanks Ziggy for the info, will check it out. Fishermark, the only way I had to check the spark was to hold the wires a 1/4 inch from ground, so that doesn't tell me the strength of the spark.

 

[wolfsterman]

Ok Ziggy, I was reading through the information that you gave, and I think I may have found the culprit. I have a tachometer that has been performing extremely erratically the last couple of times out, and I remember the motor would run a little rough when this occurred. I will disconnect it, and see what happens, and let you know. Thank you again for the info, and I will update some of my tools. Always a good thing to have plenty of tools.

 

[wolfsterman]

So, the boat is fixed. Ending up being a few problems. The tachometer was grounding out, the coil was bad, the new points were slightly different, and the most embarrassing part of all ... the spark plugs wires were all moved one position clock wise on the distributor cap, but still in the correct firing order. oooops. oh well, live and learn. Thank you all for your input.