!988 Mercury 70 hp

Dick Bacon

Seaman Apprentice
Joined
Dec 18, 2010
Messages
46
I have a 1988 Tracker deep V with a 1988 Mercury 70hp. Took it out yesterday and is started up fine. About 10 minutes into our run we hit a small wake from another boat. The motor bogged down. It went from 30 mph at wide open down to 20 mph. Rpms dropped also. After about 10 more minutes of running that sped, it kicked back in for no apparent reason and was fine for the rest of the day. Any idea what would cause that.

This is not the first time either. Sometimes I start it up and it runs great. Other times it runs slow like that for a while then will kick in and run fine. I can just about tell when it is going to run bad by the sound of motor when it starts. It has a deeper more muffled sound to it. I have cleaned carbs and installed new needles, new plugs and wires, checked for any loose connections. Any help would b appreciated.
 

Dick Bacon

Seaman Apprentice
Joined
Dec 18, 2010
Messages
46
Re: !988 Mercury 70 hp

I have read some other posts on here. Could it be the switch box ?
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,930
Re: !988 Mercury 70 hp

Possible and loose grounds on ignition plate can cause this also.....
 

Dick Bacon

Seaman Apprentice
Joined
Dec 18, 2010
Messages
46
Re: !988 Mercury 70 hp

Bought a new CDI switch box and installed it myself. The motor runs and accelerates great now
 
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