Mercruiser 170 - plan of attack to get it started

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sixman

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Just got my Four Winns 1986 190 Horizion with a Merc 170. It hasn't been started in 2 years and I haven't tried to crank it yet. Here's my current plan - please let me know if you think I'm missing something.

1. Replace impeller - seems like something I need to do just to be sure - although I'm not really sure how to test the current one.
2. Replace spark plugs & wires - spray WD40 in w/plugs out to lube it up and help get it going.
3. Replace seal on end of water cooling unit - this is currently cracked & peeled away from the cylinder and has leaked the 50/50 solution all over the bilge (is it ok to hose that out?)
4. Change the oil & filters
5. Clean the points on the distributor
6. Check fuel lines - any info on the best way to do this?
7. Gas - it currently has 3/4 of a tank of gas. Do I need to drain it? Put some stabilizer in it? Just leave it in? Not sure on this and have gotten conflicting advice.

Anything else I need to check or just replace as good measure before I try to turn it over or should I do less? I was planning on getting some earmuffs for the intake since I have a ripped bellows to make sure water is being circulated .

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Bt Doctur

Bt Doctur

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Re: Mercruiser 170 - plan of attack to get it started

A FULLY CHARGED battery is a MUST so you dont overload the charging system
remove /clean the main battery connection points,pos. and neg.
check coolant and oil and outdrive oil levels
replace fuel/water sep(if equipped)
Get it running on a remote/outboard tank first
The end caps on the heat exchanger seal the raw water side not the A/F side. A/F may have been added for the winterization
 
zbnutcase

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Re: Mercruiser 170 - plan of attack to get it started

If the fuel is 2yrs old, drain it for sure!
 
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stonyloam

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Re: Mercruiser 170 - plan of attack to get it started

I would not spray WD40 into the cylinders, use a light engine oil, like 5W30, or Marvel Mystery Oil. The antifreeze is toxic to pets,so be very careful, and catch what you flush out through the drain hole. You can sewer what comes out. If you have the plugs out, do a compression check (autozone will loan tools), to make sure you are OK there, won't be as accurate as with a warm engine, but will let you know if there is a problem with the head gasket (common with 470's). When you get it running do a cooling system pressure test (Autozone tools). If everything checks out (or not:(), welcome to the 470 club.;)
 
EddiePetty

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Re: Mercruiser 170 - plan of attack to get it started

sixman said:
.........3. Replace seal on end of water cooling unit - this is currently cracked & peeled away from the cylinder and has leaked the 50/50 solution all over the bilge (is it ok to hose that out?)
Click to expand...

This item bothers me.......though it may just be spilled or winterization A/F.

Leave the end cap(s) off the heat exchanger until you have replenished the engine coolant. If engine coolant then leaks into the bilge, that would be a sign of a ruptured tube(s) within the heat exchanger.
 
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sixman

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Re: Mercruiser 170 - plan of attack to get it started

Yeah - when I got it stuck (downhill) I think it was at an angle that caused it to spill. That's what I hope anyway.

Looking at the service records the impeller was replaced in June 07 and the carb was rebuilt then as well. Should I still replace the impeller or take a look?

Draining the fuel should be fun - is there a way to flush the fuel lines?
 
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stonyloam

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Re: Mercruiser 170 - plan of attack to get it started

3 years, replace. The impeller is critical in a 470.
 
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sixman

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Re: Mercruiser 170 - plan of attack to get it started

Makes sense - impeller first!
 
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sixman

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Re: Mercruiser 170 - plan of attack to get it started

Alright - rookie question. How do I get to the spark plugs? My usual sparkplug tool can't get in that tight spot. I got the first one out which broke but can't get at the other three with the cast iron exhaust elbow in the way.

Sounds like a new tool is in order?
 
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stonyloam

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Re: Mercruiser 170 - plan of attack to get it started

Use a spark plug socket with a hex top and use an open end wrench on it. Kind of a pain, but will work. Don't drop #4 behind the engine, last time I did it took an hour to get it out.:D
 
salty3rd

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Re: Mercruiser 170 - plan of attack to get it started

If you broke the first one, I would spray some pb blaster down towards the threads to help loosen them up. Good luck
 
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sixman

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Re: Mercruiser 170 - plan of attack to get it started

Thx guys - open ended wrench with spark plug tool w/pb blaster sounds like a good plan!

Other issue I found today - the heat exchanger seal needs to be replaced - when I took it off - the end of the exchanger was full of rubber pieces possibly from the impeller?? Seems like a bad thing!

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stonyloam

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Re: Mercruiser 170 - plan of attack to get it started

sixman said:
the end of the exchanger was full of rubber pieces possibly from the impeller?? Seems like a bad thing!
Click to expand...

Yes it is!:eek: If I read the diagram correctly the fresh water goes from the impeller to the voltage regulator then the exchanger, power steering cooler and out to the exhaust manifold, so I would pull the hoses off of the voltage regulator, and backflush to make sure there are no large chunks there, and check the power steering cooler once the exchanger is cleaned out. Nice catch:D.
 
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sixman

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Re: Mercruiser 170 - plan of attack to get it started

What's the best technique to backflush it out - garden hose? Want to make sure there isn't more for sure. I'm also trying to find a good post/video on how to take the heat exchanger out and clean it up. Same for the 50/50 mix - not sure how to drain that and make sure the cooling system is good to go.
 
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stonyloam

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Re: Mercruiser 170 - plan of attack to get it started

sixman said:
What's the best technique to backflush it out - garden hose? Want to make sure there isn't more for sure. I'm also trying to find a good post/video on how to take the heat exchanger out and clean it up. Same for the 50/50 mix - not sure how to drain that and make sure the cooling system is good to go.
Click to expand...

Hose should do it. The bottom of the heat exchanger has two plugs. Aft is seawater, fore is coolant.
 
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sixman

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Re: Mercruiser 170 - plan of attack to get it started

Does anyone know the part number for the heat exchanger end gasket? The one I took of is 4" in diameter so I'm guessing I have the larger heat exchanger but can't find any ID or info in parts listing that note if there is a dif part number or if they are all the same.
 
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