old Merc 165hp I/O (NO SPARK!!!)

[Butch Ammon]

Good afternoon...<br /><br />I have an old 1975 Sea Star 17' trihull with the old style Mercruiser 165hp inline 6 (Chevy 250ci). I winterized it like normal and left it be to sleep through the winter months here in Virginia.<br /><br />Yesterday (Sunday afternoon), I decided to open up the old gal and try to fire her up. I uncovered everything, put on the motor flusher and cranked on the garden hose water. I put just a touch of gas down the throat of the carb, connected the battery, and went to turn the key. The engine turned over and over and never started. No matter what, it didn't start. This has never happend before. I've always put a tiny teaspoon amount of gas in the carb, and she roars to life ever spring.<br /><br />But this is different.... I pulled spark plug #3 for the heck of it and it's still clean. I had my wife climb up in the boat and turn the key. I held plug #3 up against the engine block, while my wife turned the key. You guessed it.... NO SPARK! Nada... Nothing...<br /><br />Could the coil be cold and damp or wet? I put a new distributor cap/points/condensor/rotor on last summer and the boat ran like a top.<br /><br />This has me stumped. Where should I look first for a spark? The starter works and the battery is fully charged.<br /><br />Thanks...<br /><br />Butch Ammon

 

[BMDODGE]

Re: old Merc 165hp I/O (NO SPARK!!!)

it's possible the point's are "stuck" together = rust. or it's possible they could have rust on the contact's - take a good look at them - mine did they same thing, change the coil with a spare one ,still nothing..ran a piece of emery cloth threw the contacts and she fired right up<br />Bruce

 

[Sharps-Nut]

Re: old Merc 165hp I/O (NO SPARK!!!)

I am no boat mechanic but I second the problem being in the points. Coils rarely fail from just setting. Pop the cap and see if they are breaking. Check the gap and the condition of the point faces, also check and see if the coil is getting power. I have a feeling it will roar to just as it as it always does just as soon as you locate the lack if fire. I park several old cars for the winter and if they fail to come alive its usually something very simple. Good luck. Sharps-Nut

 

[mercrewser]

Re: old Merc 165hp I/O (NO SPARK!!!)

Move the throttle in an out of gear. Sometimes my circut breaker would stick closed on my 165.

 

[Butch Ammon]

Re: old Merc 165hp I/O (NO SPARK!!!)

Thanks, everyone....<br /><br />Yeah, I moved the throttle in/out of gear, and I pulled all the plugs and cleaned them off.<br /><br />The next step is to pull the distributor cap and clean the points. I'll replace the spark plug wires while I'm at it too.<br /><br />I have a buddy with one of those fancy multimeters and we'll check voltages all through the system.<br /><br />I'll get her going though. It's a classic old boat with an equally classic engine.<br /><br />Butch

 

[BadgerXXX]

Re: old Merc 165hp I/O (NO SPARK!!!)

These guys are right. 99% of the time its the points. You can open them up and sand them a bit and it will probably bring the spark back. But this is for test purposes only. If the points need sanding replace them. If you find you need points just put in a cap rotor, points and condenser. Personally I would change that $10.00 coil and the plugs too. You can basically replace the whole ignition on that motor for about $30.00 and you can clean up the old one and stow the whole mess in the boat somewhere if the new one ever fails you out at sea. <br />You can also purchase a petronix kit to convert that motor to electronic ignition for about $75.00 and never worry about points again.<br /><br />Badger

 

[Butch Ammon]

Re: old Merc 165hp I/O (NO SPARK!!!)

YES! "Lady J" lives!!! <br /><br />My old 1975 Sea Star with the 165hp Mercruiser came to life late this afternoon, after I got home from work!<br /><br />I replaced all the spark plug wires a few days ago. I also cleaned the coil wire leads, and I took the cap off and (although this might sound weird...) I put a small piece of paper in the point gap and slid it back and forth.<br /><br />Today, I figured, "what the heck", and got the motor flusher hooked up the the garden hose, etc... gave two pumps of the throttle, and VROOOOOOOM!!!!!! She started right up! <br /><br />Man, talk about a thick cloud of blue smoke and a (at first) sputtering inline 6. Once it burned off the fogging oil and additives and so on, it settled right down and purred like a kitten!<br /><br />Now I just have a clean it up a little once the weather clears up a bit, check the instrument gauges and so on.<br /><br />THEN I'LL BE OUT BOATING IN NO TIME!!!!<br /><br />Butch

 

[HULKSTERUPS]

Re: old Merc 165hp I/O (NO SPARK!!!)

so do you know why it wouldnt start ,was it the plugs or the points or was it just a cloudy day ?

 

[Butch Ammon]

Re: old Merc 165hp I/O (NO SPARK!!!)

The old plug wires were bad. You guys are going to laugh hysterically, but the terminal leads of #6 and #2 plug wires actually BROKE on the distributor cap! (I fished them out with tweezers).<br /><br />Then, I cleaned the points, cleaned other electrical connections, put the cap back on, then one by one, I replace all the spark plug wires with brand new ones.<br /><br />....Live and learn. Old corroded plug wires/broken wires, have to be replaced before doing any further checks on ignition.<br /><br />{ slaps forehead and says, "Duh"! } <br /><br />Butch