Re: Throttle assembly 1988 Sundancer 268
Generally boat controls are made by a very few manufacturers that serve the industry. So finding one that works for your boat should be no problem. All you really need to know is what brand cables are attached to the control you have now to get an aftermarket unit. Or, if you want to get an exact replacement, take a picture of it and post it and we can find it for you.
The control you have now will be made by Mercury or it will be an aftermarket unit that Searay installed. Either way it should be real common. In my area shop rates run in the $80-$150 per hour at the marinas. I would be surprised if it takes longer than a couple of hours to replace.
$300 to $500 would be reasonable. However, these controls are very simple to replace. You can be walked through it if you want to buy it and install it yourself. It would save you allot of money.