Re: mercruiser 165 runs rough when engaging drive
Welcome to iBoats.
There's a module that cuts the engine out when shifting. If it's messed up or not adjusted it'll kill the engine when you don't want it to.
Check into the ADULTS ONLY section of this forum for info on a manual for your drive. It will contain the adjustment/check procedure for this issue.
It's a module on an OMC, but not on a Mercruiser. It is a simple kill switch (microswitch) mounted in the shift cable mechanism in the back of the motor on the top, that momentarily kills the motor when shifting. These go out of adjustment sometimes, especially if the lower shift cable gets worn, if the adjustment procedure (in the service manual) doesn't work, then you need to replace the lower cable, it's not that hard, but of course the drive has to come off

But, I don't think the bellhousing has to?