redneck joe
Supreme Mariner
- Joined
- Mar 18, 2009
- Messages
- 12,147
Re: Carver 2357 Montego
Re: Carver 2357 Montego
then we had some discussion about the lower unit
Only the bottom half of the outdrive is common. The only thing the bottom half does is shift between forward, neutral and reverse. The top end of the outdrive is SPCIFIC to the engine and may have different sized shaft, different number of splines, different gimbal pins, different size bearings, etc. - depending on the engine, not the horsepower. Different cid, torque, power to speed curve is all 'adjusted' in the gear ratio to match the top half to the engine. The propeller diameter and pitch is designed to match to the hull type and weight, which has everything to do with the plane speed. The wrong prop will seriously affect performance.
Another, usually overlooked Mercruiser outdrive 'service', is the top end has a water jacket that is supposed to help cool the top bearing and oil reservoir. The jacket gets it's water supply from the impeller pump at the top of the tube that goes between the impeller and the top end. The hole that allows water into the jacket will plug up and there will be no water in the jacket to help cool the top bearing and oil causing the bearing to eventually fail (ask me how I know). If it's never been serviced it is impossible to get the bolts out without breaking them, making it impossible (or very expensive) to fix. Don't try to take them out - the rubber tube seal can be replaced without removing the plate.
There are two very small holes in the outdrive (one on each side) that allow water to escape that also plug up. They are at the rear of the outdrive between the bottom and the next to the bottom little cooling fins - look hard - you'll find them - use a needle or stiff wire to make sure they are open. There should be a bit of water leaking from them when the engine is running, no water = no water cooling the top end. Google 'outdrive cooler' or 'outdrive shower' to see how to correct the problem if there is no water getting to the jacket. This is just a 'heads up' - if you have water coming from the holes when the engine is running, you don't have a problem.
Re: Carver 2357 Montego
then we had some discussion about the lower unit
Only the bottom half of the outdrive is common. The only thing the bottom half does is shift between forward, neutral and reverse. The top end of the outdrive is SPCIFIC to the engine and may have different sized shaft, different number of splines, different gimbal pins, different size bearings, etc. - depending on the engine, not the horsepower. Different cid, torque, power to speed curve is all 'adjusted' in the gear ratio to match the top half to the engine. The propeller diameter and pitch is designed to match to the hull type and weight, which has everything to do with the plane speed. The wrong prop will seriously affect performance.
Another, usually overlooked Mercruiser outdrive 'service', is the top end has a water jacket that is supposed to help cool the top bearing and oil reservoir. The jacket gets it's water supply from the impeller pump at the top of the tube that goes between the impeller and the top end. The hole that allows water into the jacket will plug up and there will be no water in the jacket to help cool the top bearing and oil causing the bearing to eventually fail (ask me how I know). If it's never been serviced it is impossible to get the bolts out without breaking them, making it impossible (or very expensive) to fix. Don't try to take them out - the rubber tube seal can be replaced without removing the plate.
There are two very small holes in the outdrive (one on each side) that allow water to escape that also plug up. They are at the rear of the outdrive between the bottom and the next to the bottom little cooling fins - look hard - you'll find them - use a needle or stiff wire to make sure they are open. There should be a bit of water leaking from them when the engine is running, no water = no water cooling the top end. Google 'outdrive cooler' or 'outdrive shower' to see how to correct the problem if there is no water getting to the jacket. This is just a 'heads up' - if you have water coming from the holes when the engine is running, you don't have a problem.
