Need help with Mercruiser 170, 1985 model

Joined
Oct 21, 2014
Messages
18
OK, I'm about to pick this boat up FREE of charge from a family member. It is a 1985 Seville with only 52 hours on it. It has been in storage all its life when it was not used. I know nothing about inboard engines. Looks like I have a a holding tank with antifreeze that needs a new cap. How does this cooling system work? I have looked all over the internet and am confused on the many different options that are there. Here are a few pics I took a few months ago when I looked at the boat.
 

Attachments

  • 0503141028_zpsbgzqwvim.jpg
    0503141028_zpsbgzqwvim.jpg
    93.9 KB · Views: 0

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
OK, I'm about to pick this boat up FREE of charge from a family member. It is a 1985 Seville with only 52 hours on it. It has been in storage all its life when it was not used. I know nothing about inboard engines. Looks like I have a a holding tank with antifreeze that needs a new cap. How does this cooling system work? I have looked all over the internet and am confused on the many different options that are there. Here are a few pics I took a few months ago when I looked at the boat.

:welcome: to iboats

Your holding tank is a heat exchanger and works like a radiator on a car. Difference is a radiator uses air to pull heat out of the engine coolant, and a heat exchanger uses water to pull the heat out.
Look below for the manual for your engine it is manual No 8

http://boatinfo.no/lib/mercruiser/ma...uiser8.html#/0
 
Joined
Oct 21, 2014
Messages
18
So when I winterize the boat, where do I need to remove the water from? I have read articles about pulling the freeze plugs on the block but if I have antifreeze in the block then that would be OK over the winter.
 
Joined
Mar 27, 2010
Messages
3,008
You have to drain the seawater out of the heat exchanger. There should be 2-drain plugs on the stern end at the bottom. The one closest to the stern is the seawater, the other is coolant (antifreeze).
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
If it has been sitting all that time I assume that it has antifreeze in the block. It should be filled with 50/50 automotive antifreeze. To winterize all you need to do is 1) check the antifreeze in the reservoir with a antifreeze tester (about $3), should be about 50/50 (-37 degrees F). 2) as Eric said remove the AFT plug on the underside of the exchanger (7/16 wrench) to drain the seawater. That is it! Done! no draining block or manifolds on the 470. While here, there is something that you ABSOLUTELY MUST DO before running the engine on the water, and that is replace the impeller in the outdrive! The impeller pumps cooling water into the exchanger and since it has sat for a long it without a doubt will fail and overheat your engine. You should pull the outdrive and check the gimbal bearing and lube the u-joints and change the impeller. Not too bad of a job. You will need a socket set (1/4, 3/8 and 1/2 drives SAE), a torque wrench, an alignment bar, and some screwdrivers. Before you start it you will want to change the points and get yourself a timing light and dwell meter. The carb may or may not need to be rebuilt, time will tell. here is your engine manual: http://boatinfo.no/lib/mercruiser/manuals/mercruiser8.html#/0 outdrive manual: http://boatinfo.no/lib/mercruiser/manuals/mercruiser6.html#/0 Lots of help here when you need it. Welcome to the "470 club" :eek:;)
 

dpoff

Petty Officer 2nd Class
Joined
Nov 27, 2004
Messages
169
You`ll be wanting to get rid of that bad fuel also before you crank it up!
 

Blueghost924

Petty Officer 1st Class
Joined
Sep 19, 2013
Messages
250
Nice looking 470. There are many different opinions over the 470 engine, but I like it!
 
Joined
Oct 21, 2014
Messages
18
0503141027_zpscuquqiqt.jpg Thanks for all the info and input. I picked it up today from the marine. They put it in the water and fired it up, and it ran. let it run for about 5 minutes and it all looked OK. Can you please look at the antifreeze holding tank in the pick above and tell me what I need to do to get that part repaired? It looks like the lip the the radiator cap tightens to is broke off. I have the piece as it was laying on top of the engine. Just not sure if the whole tank needs replacing or if I can just replace the broken piece. It was dark when I got it home so I will look at it more closely tomorrow.
 
Last edited:
Joined
Oct 21, 2014
Messages
18
I got the boat fired up today and ran it for about 10 mins on the ear muffs. This thing has the original bimini top and a full rear enclosure. It also has the snap in play pen cover for the front bow of the boat. The material is all in great shape just needs some cleaning. It even has side windows to snap in. They are a little yellowed. What can I use to clean the material, and is there anything to get the windows back to clear?
 

BlueNote2

Petty Officer 3rd Class
Joined
Nov 30, 2014
Messages
80
Didn't know if you needed or wanted an answer on this, but just did the same to my boat, so I thought I'd mention it.


I used a couple magic erasers to clean up my interior seats and vinyl top. It is a little bit of effort, but it works and most people consider it safe. Do not use on "clear" plastics as it is slightly abrasive and may scuff.

Avoid using ANY solvent on anything plastic/vinyl/acrylic, as it will melt, discolor, or cause blemishes. I used windex w/o ammonia just to clean it, but the attached video recommends Pledge w/o Lemon. Plain water is always safe.
https://www.youtube.com/watch?v=dZeeE4sEFhQ

Here's a couple links to a UV yellowing solution. Never tried it on clears, but if you feel daring here it is.
Let me know if it works!
https://www.youtube.com/watch?v=VU7vXMezW_I
https://www.youtube.com/watch?v=fJW7xFcCya0


Bleach is not recommended as a cleaning agent, as it erodes threading. However, used sparingly it is not a problem. Bleach is the only chemical that kills Mildew/Mold spore- trust me on this.

I had severe mildew, so I added: (1) cup of bleach to (1) gallon warm water.
Use damp rag or soft nylon brush with solution to gently scrub surface.
Afterwards, rinse with clean water to remove any remaining bleach from surface.
Cleans up very nicely.

Otherwise, a mild dish soap and warm water is better.

*(a canvas repair person recommended hot-glue and a cold metal slab to fix tears in vinyl- this is skilled work, but I used it on a couple small tears and it works well)
 
Last edited:
Top