MERCRUISER 120 HP START UP

[jbu08873]

I'm new to boating a bought a boat with a bad motor.... It has a Mercruiser 120 4 cyl motor the boat is a 1981 Galaxy 170 BR. Heres the question, How do I check the engine without driving it over to the lake each time I work on it. I know on oatboards there are muffs you can use along with a garden hose to cool the engine and not blow the water pump. How do you do this on a I/O?

 

[MRS]

Re: MERCRUISER 120 HP START UP

First buy a manual for your motor. Second use muffs like on the outboard.

 

[jbu08873]

Re: MERCRUISER 120 HP START UP

It's an Inboard, and I did buy the manual, it just keeps saying do not run egine for even 5 seconds without having outdrive in water

 

[Alumarine]

Re: MERCRUISER 120 HP START UP

On the drive leg just above the propeller you'll find a number of holes on either side of the leg.<br />The muffs go on there.<br /><br />

 

[jbu08873]

Re: MERCRUISER 120 HP START UP

But where do you connect the water? I see a water pump on the engine but what about the outdrive

 

[Don S]

Re: MERCRUISER 120 HP START UP

After reading your replies to the suggestions, I would suggest you take the boat to a Mercruiser dealer and have them SHOW you how it's done with muffs, and also explain the cooling system to you.<br />The engine water pump (the one you can see), is actually known as a circulation pump for the cooling water.<br />The raw water pump is in the outdrive on most Merc Alpha drives, and probably all 3.0L engines.<br />Both pumps and the thermostat are required for proper cooling

 

[paultek6]

Re: MERCRUISER 120 HP START UP

Muffs dont have the greatest seal when installed do not run engine over 1000rpm for too long.<br />And also if you have a running problem with your engine sometimes it must be under a load so you either have to lauch it and run it or have it put on dyno.Running it under load will let you know whether you have a problem with carb,plug wires,coil and so .You will find that most times you wont find your problems just running it on muffs<br /> Paul