1974 150 hp Merc engine cutting out

Muppet

Cadet
Joined
Jun 5, 2005
Messages
28
Engine has new plugs, rebuilt carbs, sounds great. It runs ok when I first start it and it's cold, I can get about 5-10 mins out of it then it starts to get weird. Mortor will sputter, like a cyl is not firing and will just fully shut off at times. After this starts to happen I can get like 30secs to a min out of it before it shuts off again, if i can even get it started. Sometimes the only time it runs is when I have the key on start. <br /><br />When the key is in the on positon I can hear sparks, random sparks. When we had the cap off I turned the key to on and my friend saw a huge spark go around inside the cap. <br /><br />He thinks it's the distrupter, but I think it could be the coil. <br /><br />It's a old inline 6. Anyone have any ideas? it has brand new plugs also. <br /><br />Also a 2 cycle. <br /><br /><br />Nick
 

Laddies

Banned
Joined
Sep 10, 2004
Messages
12,218
Re: 1974 150 hp Merc engine cutting out

Be cause the engine has to run a few minites before it acts up it's propably ign. no interupeter switch anbd a bad box don't ussally recover, I have never replaced a large coil on those ign. systems but have a few of the smaller ones
 

OperativeK

Petty Officer 2nd Class
Joined
Apr 21, 2005
Messages
154
Re: 1974 150 hp Merc engine cutting out

Wow you hear? sparking??? If so you may want to open up the MercControl unit and have a look. You may just want to short the ignition in the rear to the ingnition wire and see if it runs fine with that. If so you would know it is the ignition at the front. If you don't know the wiring diagrahm let me know Ill post it.
 

Muppet

Cadet
Joined
Jun 5, 2005
Messages
28
Re: 1974 150 hp Merc engine cutting out

If you can toss me the diagrahm, his is my first motor like this and first boat.
 

timmathis

Lieutenant
Joined
Apr 24, 2005
Messages
1,295
Re: 1974 150 hp Merc engine cutting out

Be sure that tour tank is vented! And clean your Dis.cap.
 
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