merc thunderbolt 1150 mount problem

I was recently given a 69 starcraft c-gull with a merc 1150 thunderbolt on it. Today was my first voyage with it, and my first voyage ever driving a boat. It ran ok until I hit the prop off the bottom by accident and now the upper engine mounts are loose. I can pull the motor fore and aft about 3/4 inch at the top. I also need to reseal the lower unit as it got water in it. is there an easy way to replace the uppers? As it looks in my manual, the power head must come off. Any opinions? Thanks.

Re: merc thunderbolt 1150 mount problem

ajkustra said:

I was recently given a 69 starcraft c-gull with a merc 1150 thunderbolt on it. Today was my first voyage with it, and my first voyage ever driving a boat. It ran ok until I hit the prop off the bottom by accident and now the upper engine mounts are loose. I can pull the motor fore and aft about 3/4 inch at the top. I also need to reseal the lower unit as it got water in it. is there an easy way to replace the uppers? As it looks in my manual, the power head must come off. Any opinions? Thanks.

Click to expand...

How about some pictures of the mount and the LU.

Mark

Re: merc thunderbolt 1150 mount problem

Ill get some pictures in the morning. I did find out that its a1972. It has no power trim or tilt. Serial no 3273314.

Re: merc thunderbolt 1150 mount problem

The motor mounts are rubber with a steel center and supposed to have some give to them. If you hit a rock hard enough to break the mounts I would think your prop shaft and for that matter your whole lower unit would be shattered,bent and beyond repair.There is no easy way to replace the motor mounts.There is a special tool used to remove the "nut" at the end of the bullet.I believe there is also some sort of key way that you need to line up when replacing the seals.Again if you hit something that hard that you now have water in gears I would check the run out on the prop shaft. After investing in a manual I would buy a up to date chart for the waters your boating in,there is really no excuses for bouncing off the bottom at speed.It's like never being in NYC and driving there without a map,then expecting not to get lost.

Re: merc thunderbolt 1150 mount problem

Hitting the bottom likely did not damage the upper mounts. They likely just wore out after all these years. To replace them, you need to pull the powerhead and the exhaust extension. The mount bolts will likely need to be cut to get them off. Replacement bolts (if I remember correctly) are 6" grade 8 steel 7/16" fine thread.

Re: merc thunderbolt 1150 mount problem