200 Merc Suggestions

[lmize]

I have a 1996 200 Merc Nitro series that been sitting up 3 years. Engine has less than 100 hrs on it. I drained the tank and fuel lines, put in new gas. Changed the lower unit lube. It cranked right up, but wouldn't idle. Took the carbs off and cleaned them. Cleaned the plugs.<br /><br />Started much better and idled perfectly. Put it in the water and it started, but would not idle very good. As soon as you put it in gear, it would die. Good stream of water from the pee hole. After about 10 mins of running and trying to get it to run when you put it in gear, overheating alarm goes off.<br /><br />Shut it down and back home.....<br /><br />After reading on here, I see I should decarb the engine and check compression. Other than that, what else should I try?<br /><br />Would the rough running cause the overheating?<br /><br />Thanks for any help.....

 

[Motor Boater Bill]

Re: 200 Merc Suggestions

You might have a lean condition at idle, which could be due to the carbs needing to be cleaned. Lean idle would make it die when you put it in gear and also make it run hot. If you had old gas sitting in it for three years, you may need to do the carbs again and be sure to clear all the passages with compressed air or fine wire--I prefer heavy fishing line since it won't ream out the passages and is flexible. If the carbs are not clogged up, you may just need to enrich the idle mix. Idle mix is typically adjusted with the motor warmed up and in foward. Setting idle mix in neutral will usually result in a lean idle. Hope this helps.

 

[lmize]

Re: 200 Merc Suggestions

Thanks for the reply. The repair maunal I have shows WMA carbs. Mine has WMV carbs. There is only one adjustment I can find on the carbs. It has a plastic fitting over the screw to keep it from turning all the way around. How should it be set?<br /><br />Thanks

 

[Motor Boater Bill]

Re: 200 Merc Suggestions

Sorry, I'm not familiar with your particular motor and carbs, so my comments were general. I'm sure someone here will have the specific info you need. Good luck!

 

[studlymandingo]

Re: 200 Merc Suggestions

Have yo done the decarb and compression check yet?<br /><br />I did a heavy decarb using a 1 gal to 1 can mix, did 3 cycles until the mix was used. Later, I was replacing plug wires and sprayed Deep Creep directly into each cylinder and let it sit overnight. Next day when I fired it up I got just as much crud coming out of the exhaust as I got from the first decarb. <br /><br />Reason for asking about compression and decarb is you may have a cylinder that is down in compression readings. Doing a decarb directly in the cylinders can free rings that are stuck due to deposits. <br /><br />I'm not sure about your carbs, but you can tell quite a bit about the lean/rich conditions by the state of the plugs (wet and oily or dry and powdery). Post as much of this information as you can and someone should be able to point you in the right direction!<br /><br />By the way: Welcome to iboats!

 

[lmize]

Re: 200 Merc Suggestions

Thanks, decarb is next on the agenda....

 

[studlymandingo]

Re: 200 Merc Suggestions

Also, a lean carb setting can cause the engine to get too warm, as well as rough idle.

 

[lmize]

Re: 200 Merc Suggestions

Compression checked great....will finish decarb today...<br /><br />Anyone have any pointers on setting mixture to take care of lean condition if it is in fact lean...<br /><br />It has WMV carbs....<br /><br />Thanks a lot.... This forum is great