Engine running rough

jwhalen · Post by **jwhalen** » Mon Sep 13, 2010 3:34 pm

This Sat. took my kids out and we tubed for about 2 hours 2800 rpm. Boat ran fine. We then idled for about 30 minutes at somewhere around 900 rpms as we made our way home. Decided to throttle up and it would start missing/backfiring when we would get to 1800 or higher rpm. When I took the boat out of gear and revved the engine no such problem only when it was under load. We decided to anchor and swim for about an hour. When we started back up the boat ran fine.

My thought is maybe a coil that needs replacing? Fouled plug? any ideas?

I have a 1976 Chrysler 318. It does not have points as they were removed for the electronic version.

Thanks,

John

randyp · Post by **randyp** » Mon Sep 13, 2010 5:20 pm

John, sounds like any or all of the above. When was last time you had plugs replaced? Ignition wires? Carb serviced? All of these are not break the bank type expenses and if you have a single engine like me it's worth the peace of mind knowing when you go out you can get back in!

Big D · Post by **Big D** » Mon Sep 13, 2010 6:47 pm

Check the advance mechanism in the distributor. Suspect it's sticking. Remove cap, turn the rotor by hand as far as you can then let go and see if it springs back. If it doesn't, that's your problem. Remove the rotor and check the top of the shaft for a little felt pad. If it has one, drop some oil in it. Put the rotor back on and twist it back and forth while you polish off a 24 pack! Takes a while. If that doesn't solve the sticking mechanism, remove the plate with the electronic conversion kit and inspect the wieghts and springs.

koviak · Post by **koviak** » Tue Sep 14, 2010 4:53 pm

John, my last boat had a chrysler 318 with electronic ignition and would do the exact same thing when the pick up module was going bad in the distributor. Heated up power loss, cooled down no problem. Look for replacement parts thru marinepower.com, about $95.00 (2-3 day delivery)

Dan Faith · Post by **Dan Faith** » Wed Sep 15, 2010 1:23 pm

Sounds like it could also be moisture in the distributor cap. Take it off and look for signs of moisture or a line burnt between the contacts.

fpawn1 · Post by **fpawn1** » Thu Sep 16, 2010 2:24 pm

I have learned over the yrs--not that many-- change plugs every year, caps every other, and wires about 4 yrs. I do believe in replacing belts and hoses in 5 year periods. Some say i am nuts, but for that little money, its a great piece of mind and less worries.