Merc 3.0 runs rough below 3k, fine above 3k.

[cheburashka]

This is a '74 Mercruiser 140 with Pertronix ignition. Timing is good. Up until yesterday it ran great, with the only problem being a bogging down when coming off of idle. Yesterday, it started running rough out of idle and all the way up to 3k. At that point, the engine will stumble for awhile, then suddenly smooth out and run fine all the way through the RPM range. It does great at WOT and the idle is smooth as can be.

I plan to pull the carb and check it out. It was rebuilt last summer, but something could have gone wrong in there. Any other suggestions as to how to proceed with this?

Thanks

 

[cheburashka]

Re: Merc 3.0 runs rough below 3k, fine above 3k.

I'm going to add to the previous message. I just took a look, and the filters are fine. What bothers me is that there are two problems now that I never had before. One is that the starter doesn't always engage, the other is a pretty serious oil leak. I was out for three hours yesterday and I ended up with about a quart of motor oil in the bilge. I'm wondering if these things could be connected. I'll check into posts about oil leaks, but I appreciate any information you can give me on this.

Thanks