Rough Idle

Santo Maggio

Cadet
Joined
Aug 16, 2003
Messages
9
I Have a 1989 Merc 3.7 and i'm having a problem with a rough idle and keeps stalling, I did a complete tune up set the plug gap points @022 but had to advance the timing to 10-12 deg not 8 like the book but things just don't feel right I read that some people are closing that point gap too 12 is that right or could the disturbtor have to be pulled maybe the owner befor me have pulled it at one time and its not in right, i don't have any ideas,,,,,,, Sandy
 

snapperbait

Vice Admiral
Joined
Aug 20, 2002
Messages
5,754
Re: Rough Idle

Problem might be dwell... Might need to set your points with a dwell meter...<br /><br /> Is the problem only at idle speeds? Whats it do out on the water? Cruising speeds ok?
 

Santo Maggio

Cadet
Joined
Aug 16, 2003
Messages
9
Re: Rough Idle

I don't remember out of the water, no problem at high speeds i running a 23 foot boat and wide open she runs somewhere around 30 ,, its just at that low speed , if i idle she'll stall i have to run the idle around 900 in neutral ,i din't have a dwell meter but i did gap the point at 22 , thats what the tag calls for , maybe i should close it up a little , i hate bringing it to the shop they rape you and most of the time's you still have the same problem ,don't know what i should change next ....... Sandy
 

Santo Maggio

Cadet
Joined
Aug 16, 2003
Messages
9
Re: Rough Idle

Today i pulled the carb and pick up a rebuilding kit ,,, I'll see how tat goes.......
 

airman

Petty Officer 1st Class
Joined
Aug 9, 2003
Messages
332
Re: Rough Idle

Point gap is just a starting point to set the dwell. Pick up a cheap dwell tester before you go broke buying parts and make sure.
 

Colorado Boat Nut

Seaman Apprentice
Joined
Jul 6, 2003
Messages
34
Re: Rough Idle

just a thought<br />check your plug wires with an ohm meter<br />all mine were firing but all of them were broken internally, before the new wires i had a rough idle and had to advance my timing quite a bit to smooth the idle,<br />just a thought hope it helps<br />cobonut
 

Santo Maggio

Cadet
Joined
Aug 16, 2003
Messages
9
Re: Rough Idle

Thanks Guys ,i did set the dwell a friend come over and we did it ,,,,,,,, wires are ok brand new but i will check with an ohm meter,,,,,, the carbs done and will put it on today ,,, i will let you know,,,,,,, Thanks
 

Santo Maggio

Cadet
Joined
Aug 16, 2003
Messages
9
Re: Rough Idle

Thanks for all your help ,,, Put the carb on reset everything and up and running great,,,,,, Sandy
 
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