I have a 2001 mercury 90 hp 4 stroke that is only getting to 4200 rpm’s. Motor is rated for 6000. It’s propped correctly according to all the online prop selectors. (14”x13p). It’s on a 22’ monarch pontoon. Compression is good. I did a top end rebuild last year because of low compression. Water was getting in the oil. I fixed that during the rebuild. I got the boat about 6 years ago. On the second trip out, the motor died while throttling back to stop. Smoke came from under the cowl. I found loose battery cables. I guess the guy I bought it from only finger tightened them. (My fault for not checking). That fried the regulator. I replaced it. I only realized that I should be near 6000 rpm’s during the rebuild. So I don’t know for sure if the motor ever got close to max rpm’s. I thought after I got the compression right that it would. But it doesn’t turn any more now than it did. Now it has started missing real bad at full throttle. I have to pull the throttle back to about 2500 rpm’s to smooth out then I can throttle back up. When I put an inductive timing light on the plug wires, 1 & 4 fire about twice as fast as 2 & 3. The stator tests good. The pulsar and charge coils read really low voltage but I’m not sure that I was or wasn’t getting a good reading trying to back probe them through the connector. Sorry for the long post but I know y’all like as much info as y’all can get. Any help would be appreciated and thanks in advance.
