merc 260 goes out of gear

[vinyard]

first time here so any help is appreciated. I have a 1983 mercruiser 260 recently having overheating problems, changed impeller and waterpump so i would not have to go back for awhile. boat idles fine (runs at 140degrees at idle) but gets hot fast under load above 3000 rpm for short time. also goes out of gear if you try to to accelerate fast from stop, like if you were trying to pull a skier, though this happens anytime you try to accelerate too fast. can get up to plane if i go only to half throttle but not if i try full throttle. had a mech change the gimble bearing last year and has not run properly since. he said they had to pull the motor to do so, not the lower unit but the whole motor, not sure if this is correct way but im no mechanic so i can't argue the point very well.

 

[tashasdaddy]

Re: merc 260 goes out of gear

sound like you need to adjust the shift linkage, before you ruin the lower unit gears completely.

 

[vinyard]

Re: merc 260 goes out of gear

thanks for the reply. I adjusted shift linkage and it stays in gear but seems to loose power as u accelerate. any ideas? did i ruin the lower unit? also temp gauge is going close to 200 so i shut it down but the cooling lines all seem cool from lake water and i can put my hand on the exaust manifold and it is hot but not hot enough to burn my hand. going to try an infared therm to check temp.

 

[Don S]

Re: merc 260 goes out of gear

You should be posting in the IO forum, this forum is for Outboards.

 

[WillyBWright]

Re: merc 260 goes out of gear

You might need a thermostat. But I'm betting on a broken exhaust flapper blocking the exhaust path. That would cause the motor to retain a lot of heat under load. It could also be a cracked head or leaky head gasket. All of those would be logical results from an overheat from water starvation.

I'm hoping your acceleration problem is nothing more than a spun hub in your prop. Pull it and look for shiney surfaces where the hardware meets the prop. If they're shiny, that would be a good indication. Poor acceleration could also be caused by an exhaust blockage from a failed flapper blocking the exhaust. You would have to pull the drive to see that. They typically get stuck where the shift shaft passes through the exhaust passage in the drive, or in the Y-pipe. You can usually see the latter with a flashlight with the drive removed.

Another possibility for both the hot running and poor acceleration could be a spun coupler on the flywheel. If it slips, it'll act like a spun hub in the prop with the addition of running hot due to the water pump not pumping fast enough. Spun couplers leave a strong burnt rubber smell back by the transom.

I've never had to pull a motor to change a gimbal bearing. But they can be terribly difficult to get out by pulling. Driving from the backside would be a last resort. If the engine alignment wasn't properly adjusted, that could take out a flywheel coupler.

Also, check for a kinking water hose back by the bellows in front of the drive. That would also account for a hot under load condition and you can see that easily. Check with the drive down.