91 merc. carb. w/5000rpm and no speed

I have a 200 hp motor w/ comp. of 100 on 5 cyls. and 90 on one. It idles, revs. and in gear it will get up to 5000 rpm's but has no speed. I de-carbed motor,used seperate gas supply and hose and still no luck. Recently had problem with oil pump and disconnected and am running 50/1 premix now. Would appreciate any info. from anyone with knowledge of mercury motors. Thanks

Re: 91 merc. carb. w/5000rpm and no speed

If I understand it right your motor runs ok and your prop is in good condition?<br /><br />When your motor runs 5000 rpm in gear, the prop will turn about half of this.<br /><br />If you get rpm and no speed, something prevents your prop from producing thrust when turned at proper speed. As the gears are direct the prop shaft will turn once the gear is engaged (no slipping clutch or so). <br /><br />When the prop shaft turns, the prop will turn along unless the rubber bushing between the shaft and the prop hub is spun.<br /><br />To detect this you could mark both the porp nut and the prop itself. After running these two marks must not have moved away from each other.<br /><br />If they have you need a rehub job or a new prop.