Hi, hoping someone has had this issue and can help. I have a '91 Maxum 2400 sport cuddy with a mercruiser 7.4L with a Bravo I drive. The other day I was cruising at approx. 30 mph and noticed the rpm's would spike up from about 3000 to 3500-3800 for a split second and then go back to 3000. This would happen intermittently every couple minutes on a twenty minute drive. Then as I slowed to enter the marina it needed 2000 rpm's to do 10mph. At the slip the rpm's stayed at 1000 and wouldn't drop to normal idle (600-700). When I shut the engine off and started it back up the rpms were normal. What would cause this? Dirty carb? vacuum leak? Loose tach wire? Bad tach gauge? Stretched throttle cable? I thought maybe my hub was slipping or it was prop wash until I put it into neutral at the slip and the rpms stayed at 1000-1100. Engine is a through prop exhaust so its not loud. I don't think I hear the engine rev as the rpm's spike. Engine seems to be running fine, no labouring or stalling or backfiring at any rpms. Starts fine. I don't beat it, only get it over 4000 rpm's once or twice a season for couple minutes to blow out the cobwebs otherwise it runs around 3000-3500 at 30-35mph. Engine only has 239 original hrs on it according to the meter (seems impossible yes ) I'm not discounting that's inaccurate but seems to be working. We do mostly drift down the river All other gauges read normal, temp good, oil good, battery good. Its professionally winterized every year. I understand because of its age other things might start to go like wiring harnesses and cables and gaskets/seals, hoses etc Everything appears to look fine. No visible cracks in any hoses, I don't hear any hissing anywhere. We did get into some weeds last year and the intake got clogged and cause the temp to rise fast and I burned the rubber off one of my flappers. That rattles a bit now but they didn't see any remnants in my exhaust when it was winterized last year. Any ideas or comments are welcomed
Thanks
Thanks
