Restoring a 1978 Mercury 900 90hp "Tower of Power" Need Help!

[DaxDyson]

This is my first time ever on this website, and it is my first time working on a boat or boat engine, for that matter. I was hoping that y'all could point me in the right direction for parts and reliable resources. I've been looking for a manual and so far haven't found any good PDFs. The research I've done is quite a few google searches which usually lead back to this website. So far, I know that I am missing the distributor (and what looks like a lot more). The engine will manually turn over when it's in gear, though, which is a good sign. I added some pictures to hopefully troubleshoot with you guys. Aside from missing things, it seems like it's in good condition. Thank you guys for the help! I'm excited to be a part of this forum and community.

Edit: One more note is that I haven't taken off the top cap yet, so I don't know if there is a distributor drive on the top. I'm assuming there is but that's what I'll look at next.

 

[racerone]

The motor never came with a distributor when it left the factory !!----Yes you need a manual.----Do a compression test before you spend any coins on it.

 

[DaxDyson]

The motor never came with a distributor when it left the factory !!----Yes you need a manual.----Do a compression test before you spend any coins on it.

To do so, would I manually crank the engine to get the pressure since it is currently not running? If that is the case do I do it for each cylinder?

 

[GA_Boater]

Does the starter work to turn the motor over. You don't start the motor to check compression on each cylinder.

 

[DaxDyson]

Does the starter work to turn the motor over. You don't start the motor to check compression on each cylinder.

At the moment I got the motor to turn over from turning the propeller with my hands. I put it into gear and turned it like you would the flywheel in a car. Finding information on it has been the main task right now, so I haven't been able to test the starter. What would you suggest at this point?

 

[racerone]

Best order a workshop manual I say.

 

[GA_Boater]

Best order a workshop manual I say.

Agreed! Winging it can be very expensive.

 

[merc850]

You will need the serial Nr. before you try to get a manual, the Nr. might be on the clamp bracket, between the clamps, or on the block near the starter.

 

[Chris1956]

That is not a 1978. It is a late model 1979 or newer, as distributors were phased out on the IL6 in early 1979.

Jumper the starter to turn the engine over and test the compression. All cylinders should be within 15% of each other. if that checks out, check for spark. You can turn the ignition key on and jumper the starter and spark should occur.

 

[DaxDyson]

You will need the serial Nr. before you try to get a manual, the Nr. might be on the clamp bracket, between the clamps, or on the block near the starter.

What's the best way to find it once I have the serial number?

 

[DaxDyson]

That is not a 1978. It is a late model 1979 or newer, as distributors were phased out on the IL6 in early 1979.

Jumper the starter to turn the engine over and test the compression. All cylinders should be within 15% of each other. if that checks out, check for spark. You can turn the ignition key on and jumper the starter and spark should occur.

Thank you! I rechecked the title and you're right. This weekend is a little warmer so that's the next order of business, I have to borrow a compression gauge from a friend.