1989 mercury 200hp 4 ignition question

I have a on going problem. My 200 hp mercury runs funny. At cold start up and idle she runs fine but after leaving the no-wake zone (after about 1.5 miles at 5mph), and i open her up she is running on say 4 cylinders, then after a short while the other two kick in and she will run great for the rest of they day (not always though). Are my lower cylinders loading up with fuel? should i replace the power packs?<br />It seems to be a elelctrical problem, but who knows. Any help would be great!!!<br /><br />Thank you

Re: 1989 mercury 200hp 4 ignition question

Hello Mr Nypd,<br /><br />Welcome to iBoats.<br /><br />Try to isolate which cylinders, I know that's not going to be easy. <br /><br />If it's pair with a carb in common, then the carb is a good bet. Also be aware that the triggers for the sparks are paired as well. The pairing is 1&4, 2&5, 3&6. The pairing for the carbs is 1&2, 3&4, 5&6. Each power pack does 3 cylinders; 1,3,5 and 2,4,6.<br /><br />Hope this helps, and gives you somewhere to start.<br /><br />Chris...........

Re: 1989 mercury 200hp 4 ignition question

thanks chris,<br /><br />I seem to have three power packs and they look as if each one runs two cylinders, I cant see what your describing (each pack runs three cylinders, there is definatly two ignition wire leaving each pack. could i have a different motor than what your discribing?

Re: 1989 mercury 200hp 4 ignition question

Those packs you're looking at (on the exhaust cover at the back of the enigne) are coils. There is 2 coils in each of the metal housings that cover them. Go to the starboard side of the engine and you'll see A rectangular metal box with 4 wires along the top and about 6 wires down the centre. There are 2 of those, one behind the other. Those are the power packs (correct Merc name - Switch boxes). <br /><br />The triggers are up under the flywheel. If you can see those you have a far more serious problem. <br /><br />Chris...............

Re: 1989 mercury 200hp 4 ignition question

ok i see now, should i replace the coils could that be giving me the symptoms that i am experiencing?

Re: 1989 mercury 200hp 4 ignition question

Nypd,<br /><br />There are 2 types of mechanics. 1. troubleshooters and 2. shotgun.<br /><br />Troubleshooters diagnose the problem and then replace the appropiate part(s) or make the necessary adjustments, shotgunners just replace parts until the problem goes away. <br /><br />We'll be taking the troubleshooting approach here (I hope )<br /><br />It's unlikely that the coils are the problem. The first task is to determine if the problem is electrical or fuel.<br /><br />If the problem is fuel we could replace the entire ignition system and still not fix anything, more likely introduce another problem. So let's find out what's actually happening.<br /><br />Chris..............

Re: 1989 mercury 200hp 4 ignition question

Chris, <br />Thanks for your help and direction here. Being that the coils are original equipment from 1989 replacing old parts before they fail is called preventitive maintance. so in my limited understanding of marine mechanics it would not be the worst thing to replace my coils. Having owned and operated a limousine company with 22 vehicles in the fleet for the past 16 years, I am very familar with keeping vehicles running and replacing parts before they fail. I thank you for your direction and help. I will keep you posted<br /><br />thanks again<br />john

Re: 1989 mercury 200hp 4 ignition question

If a plug check shows the top two cylinders, or any opposite pair of cylinders fouling (running dark) <br />I would look at the reeds ...<br />the carbs are seperate to each cylinder, just joined at middle..i/e seperate float ,jets ,and throttleplate..<br />but the reed cage has a common passage hole in it ..<br />so if one reed is blowing back , it will foul the opposing cylinder, and vice -verse..<br />this only happens at low rpm..<br />results one or more plugs fouled,until the rpm "burns off the excess fuel"<br />then runs fine untill another extended idle period<br />sometimes you can look into the carb openings at idle, and see the "puddling in carb throat.<br />the puddling is what that is 'sucked in" when you roll on the throttle..<br />result ..runs like crap untill the plug clears

Re: 1989 mercury 200hp 4 ignition question

now we are getting somewhere?<br /><br />I'll report back after todays attempts<br /><br />peace<br /><br />john