Plug on bottom of boat??


Old 07-31-08, 08:01 PM
Thread Starter
Join Date: Jul 2008
Posts: 5
Plug on bottom of boat??

i am an auto mechanic, but am new to the boating scene. i recently purchased a 1976 silverline comoro runabout with a ford 302 I/O motor. I live about an hour from the lake and want to start my boat up before i go out there, since it hasen't been ran in a while. i have the suction cup thingy that attaches to the garden hose to hook up water supply, but i can't figure out where it goes. also, there is a threaded hole at the rear bottom outside of the boat, under the outdrive. is this where the water intake for the motor is?? or is it a drain plug i need to have plugged up with a threaded insert?? i don't want to get to the lake and sink!!
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Old 08-01-08, 04:14 AM
Join Date: Apr 2007
Location: Near Buffalo, NY
Posts: 4,239
I'm guessing it's a Mercruiser outdrive. If not, please correct me.

The water intake slots are just above the transmission -- the round bullet-shaped section that feeds the prop. Slide the muffs on from the front and make sure they're covering as much of the slots on both sides as possible. Turn the water on before running the boat. Within a few seconds you should see water exiting from the center of the prop and from under the bottom of the gimbal where the lower unit is attached. (Both are exhausts.)

Don't rev the engine above about 1500 rpm or you could flatten the hose and choke off the water supply. Never run it without water. The rubber impellor in the water pump can be damaged in as little as 20 seconds.

Since you're new to it, you should also know that there are lube points on the gimbal. Use Quicksilver/Mercury 2-4-C lubricant. Also, the stern drive itself is filled with gear lube (use the High Performance stuff, it has better emulsifiers) that should be changed before and after every season. Bearing Buddies on your trailer and the power steering ram (if it has one) also use the 2-4-C.

The threaded hole at the bottom of the transom's V is the drain. Drain plugs are sold at all marinas and marine retail stores. Usually a brass fitting (that doesn't require teflon tape).
Old 08-01-08, 05:27 AM
Thread Starter
Join Date: Jul 2008
Posts: 5
rick you saved the day! yes, sorry i did not post it is a mercruiser. i did find the small slots on the bottom of the outdrive last night about 11 pm and was curious that those might be it, thanks for confirming that. and thank goodness i know i need a plug for my boat or i would have sank! thanks again

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