1991 454 Bravo/Century 5500CLX

[Allout123]

Hello! I am new to the forum, I also posted in another thread about my boat, but I thought this would be more geared to my questions specifically for the engine.

I just bought my first boat that's not an outboard, a 1991 Century 550CLX with the 454/Bravo.

I have spent a lot of time searching the forums for information, but I figured I could ask some of my dumb questions straight out instead of thinking I'm doing something right since this is my first "real" boat. These may sound stupid but I would really appreciate the reassurance!

For de-winterization this spring, is there a procedure that you guys follow for a combo like this? Such as where are the drain locations for coolant, etc. As far as I understand, this works by using contained engine coolant and a heat exchanger, and an impeller/freshwater pump to cool that exchanger, am I correct?

In terms of replacement parts, such as a distributor cap, are mercruiser parts specific or can I just go to a local parts store and grab one for a similar 1991 454 and interchange them?

And lastly, what types/weights of engine oil/gear oil/coolant should I be putting in this bad boy? Unfortunately there is no manual with it and I looked like crazy online but couldn't find one! My serial number is 0D447196.

Thank you so much!

 

[Bondo]

As far as I understand, this works by using contained engine coolant and a heat exchanger, and an impeller/freshwater pump to cool that exchanger, am I correct?

Ayuh,..... Welcome Aboard,.... Closed coolin' isn't Standard, so do you See a radiator cap on a heat exchanger,..??
If not, it's raw water cooled,...

In terms of replacement parts, such as a distributor cap, are mercruiser parts specific or can I just go to a local parts store and grab one for a similar 1991 454 and interchange them?

The Ignition is Merc's own T-Bolt IV, so the cap is Merc specific,...
Spark plugs oughta be AC Delco, MR434T,...

And lastly, what types/weights of engine oil/gear oil/coolant should I be putting in this bad boy?

IF it's closed coolin', plain ole 50/50 antifreeze,... otherwise, it cools with the water under the boat,...
I run Shell Rotella T 15W-40 in the entire fleet for motor oil,...
For the drive, use a Syn-oil, I use Mobil 1 or Valvoline 75W-90,....
P/S, 'n trim uses Atf or 10W hyd. oil,...

 

[Allout123]

Ayuh,..... Welcome Aboard,.... Closed coolin' isn't Standard, so do you See a radiator cap on a heat exchanger,..??
If not, it's raw water cooled,...

The Ignition is Merc's own T-Bolt IV, so the cap is Merc specific,...
Spark plugs oughta be AC Delco, MR434T,...


IF it's closed coolin', plain ole 50/50 antifreeze,... otherwise, it cools with the water under the boat,...
I run Shell Rotella T 15W-40 in the entire fleet for motor oil,...
For the drive, use a Syn-oil, I use Mobil 1 or Valvoline 75W-90,....
P/S, 'n trim uses Atf or 10W hyd. oil,...

Thanks a ton, I appreciate the info! I just towed it home last night, I could have sworn I saw a coolant overflow reservoir in the back of the engine bay when I glanced last night, but I may be wrong! Will double check tonight.

As far as the engine oil, if I don't run Rotella, will any 15w-40 should be a good fit? (I love Mobil 1 synthetics, I'll probably use that if synthetic is okay to run in these)

Do you swap out your power steering/trim fluid every spring? I was wondering if it was worth doing.

If I recall, someone once told me the fuel pump is somehow connected to the impeller on these, have you ever replaced them? He made it sound to me like save the trouble and just take it somewhere instead of DIY, but I don't mind a challenge! Haha

 

[Bondo]

As far as the engine oil, if I don't run Rotella, will any 15w-40 should be a good fit? (I love Mobil 1 synthetics, I'll probably use that if synthetic is okay to run in these)

Do you swap out your power steering/trim fluid every spring? I was wondering if it was worth doing.

If I recall, someone once told me the fuel pump is somehow connected to the impeller on these, have you ever replaced them? He made it sound to me like save the trouble and just take it somewhere instead of DIY, but I don't mind a challenge! Haha

Ayuh,.... As for motor oil, it's like Opinions, 'n buttholes, We've All got 1, 'n no 2 match,...
I used to run Mobil 1, 15W-50, but decided it ain't worth the extra money, changin' it every year,.... not enough hours,...

P/S, 'n trim oils get changed only if contaminated with water,....

'n Ya, yer mechanical fuel pump is driven on the same bracket/ assembly as the raw water pump,....
Best practice I know is to remove the Whole thing, rebuild the raw water pump, 'n make sure there's gear oil in the cavity 'tween the 2 pumps, so it don't burn itself up,...

 

[Alumarine]

The remote reservoir you saw may be for lower end gear oil.

 

[wrench 3]

The remote reservoir you saw may be for lower end gear oil.

Or trim tabs.