1978 Chrysler 25HP Only One Plug Sparks

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nicktheww2fanatic

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Hey guys, I'm hoping you can help me out here as I know absolutely nothing about motors.

I have a 1978 25HP Chrysler Outboard model #256H8C. Last weekend out on the water it worked on the way out, but when we tried to change locations, I was unable to start the motor. I was messing with the motor trying to get it started today, and decided to change out the spark plugs. Once I replaced the spark plugs, it seemed like it was almost starting, so I decided to see if both were sparking. Well, only one is sparking. So, I'm guessing that I found why the motor won't start. Um, how do I fix this?

Also, at first when I turned the key, it seemed like the starter motor couldn't turn whatever its supposed to turn, so I pulled the starter rope out until it rotated a bit, then when I turned the key, the starter motor was able to get the motor to turn over.

Thanks,
 
Sounds like 2 separate issues. For the starting problem, the first thing I would look at is the battery (make sure it's fully charged and if it's an older battery, load test it) and the connections to the battery (make sure they are clean and tight).

For the lost spark, first thing you should do is swap the plugs and make sure the one that's not sparking now will spark when installed in the other plug wire, you could have a new defective plug. Next you need to check the plug wire to make sure it hasn't gone bad. If that's good you might try swapping the coils and see if the lost spark follows the coil.
 
[url=https://www.tinboats.net/forum/viewtopic.php?p=323548#p323548 said:
JMichael » 40 minutes ago[/url]"]Sounds like 2 separate issues. For the starting problem, the first thing I would look at is the battery (make sure it's fully charged and if it's an older battery, load test it) and the connections to the battery (make sure they are clean and tight).
I used 2 different batteries, one of which is almost new (only a few months old), and both were fully charged & ran my trolling motor just fine. All connections were clean and tight.


For the lost spark, first thing you should do is swap the plugs and make sure the one that's not sparking now will spark when installed in the other plug wire, you could have a new defective plug. Next you need to check the plug wire to make sure it hasn't gone bad. If that's good you might try swapping the coils and see if the lost spark follows the coil.
I swapped the plugs, same place had no spark. How do I check the plug wire? Is swapping the coil just undoing a few screws & refastening them?
Click to expand...
 
The starter could have an internal problem with the brushes, armature (commutator), bearings, etc. If it continues to give you problems, you might want to have it tested and/or rebuilt.

If the plug wires are not the type that are molded to the coil you could just install the wire with the lost spark problem on the other coil and see if you get spark with it. As for switching the coils, depending on your motor, it might be easier to just swap the input wires to the coils long enough to check for spark on the cylinder that has lost spark now. Be sure to have the plugs removed from the cylinders to do this test and switch the input wires back to their original position after you've finished testing.
 
Well, I was able to get both plugs to spark. I took apart the spark plug boot & stripped a bit more of the wire. Now I will wait until tomorrow before trying to fire up the motor (Don't think the neighbors would appreciate me starting it even if it is in my garage).

Wish me luck.
 
Be sure you're running it in a barrel of water or on muffs. You never want to run it dry even for a few seconds or you could damage your water pump impeller. Good luck with it.
 
[url=https://www.tinboats.net/forum/viewtopic.php?p=323825#p323825 said:
JMichael » Today, 09:29[/url]"]Be sure you're running it in a barrel of water or on muffs. You never want to run it dry even for a few seconds or you could damage your water pump impeller. Good luck with it.
Click to expand...


Thanks for the reminder. I had the motor in water (big industrial tub). Anyways, no go on the motor. It still wouldn't catch, at first it almost sounded like it did, but then it didn't even begin... After a bit of me trying (turning the key over & over) it looks like some sort of black fluid (oily gas most likely) was leaking into the tub of water. Not really sure where to go now.

What should I be looking at now?
 
Stick to the basics. Check to be sure you have a strong blue spark on both cylinders and check that the plugs get wet with gas when you try to start it. If it's missing either one of those then you start checking it to find out why. If the spark is weak or orange that is a problem.
 
[url=https://www.tinboats.net/forum/viewtopic.php?p=323876#p323876 said:
JMichael » 8 minutes ago[/url]"]Stick to the basics. Check to be sure you have a strong blue spark on both cylinders and check that the plugs get wet with gas when you try to start it. If it's missing either one of those then you start checking it to find out why. If the spark is weak or orange that is a problem.
Click to expand...

So try and start it a couple of times, pull the plugs & see if they are damp?
 

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