Bringing 1978 470 to trouble free boating in 2011

kanada

Petty Officer 3rd Class
Joined
Mar 15, 2011
Messages
76
Hi Gang!

here is a brief history:

Early this spring me & my buddy bought 1978 Aristocraft 19 with 470 in it (5694572) with MC1 (4914682).
So far for the boat we reupholstered seats and had to change the steering cable - was almost frozen.

We took her out on the lake and stalled - could not restart.

Then we got into the motor:

- rebuilt fuel pump
- rebuilt carburetor
- new temp sending unit
- new gauges: water temp, volts, oil pressure, fuel level.

ran just fine on muffs, took her out again - engine just died and would not restart.
No spark this time, disconnected tachometer sending wire and we running again.

got new tach, replaced, took her out for a 3 day camping weekend - all was good until we needed to head back to the ramp.
Trim pump just stop with the leg half way down. We limped 1-2 miles back to the ramp.

The cause - trim pump motor brushes worn to noting :)

Up to this point all our trips where 1-2 miles short runs to the island beaches and back to the ramp.

We took her out this Sunday for a fishing trip. Water temp @85.
She always ran around 190, but coming back the temp slowly crept up to 200-210 mark. Running @3000 rpm for 20 mins.
That is just way to hot in my book.

I took the lower unit off Monday. Impeller is in tact, just a bit tired. (new kit has shipped already).
New 160 deg thermostat is on the way too. I will be opening the heat exchanger for cleaning/inspection too.

Is there anything else I am overlooking?
Should I hook up water hose to the heat exchanger input hose and see is there is unrestricted flow out of the upper unit? the lower is off now.

Where else water flow can be restricted?

Appreciate all your tips.
 

stonyloam

Vice Admiral
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5,827
Re: Bringing 1978 470 to trouble free boating in 2011

Welcome to the world of old boats LOL. Checking flow back through the upper is a good idea to make sure the hose is not kinked. For the impeller, I don't know what is in your kit, but I would replace the housing along with the impeller, especially on a boat that old. Cleaning the exchanger is a good idea too. One thing with the exchanger, make sure the end gaskets are in really good shape, because the water flows back and forth through the exchanger a few times before exiting and a poor seal on the ends will let the water "short circuit" some of the tubes so you don't get maximum cooling. The only other restriction point is on the exhaust elbow. Make sure you get good flow there so the seawater can exit freely. Keep an eye on the little weep hole on the engine waterpump. If it starts leaking you will have to replace the cam seals (no big deal). You should probably do a compression test when you get a chance just to make sure your head gasket is in good shape. Have fun, and welcome to the "470 club":facepalm:;).
 

kanada

Petty Officer 3rd Class
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Mar 15, 2011
Messages
76
Re: Bringing 1978 470 to trouble free boating in 2011

Thanks!

Kit includes impeller housing.
What is the easiest way to check exhaust elbow flow? hook up the hose to the heat exchanger exit hose will do it?
 

Don S

Honorary Moderator Emeritus
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Messages
62,321
Re: Bringing 1978 470 to trouble free boating in 2011

Remove the elbow and look at it. If the water passages are plugged up, replace the elbow.
 

stonyloam

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Re: Bringing 1978 470 to trouble free boating in 2011

What Don says. That would also be a good time to take a look at your exhaust shutters.
 

kanada

Petty Officer 3rd Class
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Mar 15, 2011
Messages
76
Re: Bringing 1978 470 to trouble free boating in 2011

easier said then done.
Probably engine or gas tank has to come out to get to it :(

View attachment 107214
 

stonyloam

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5,827
Re: Bringing 1978 470 to trouble free boating in 2011

easier said then done.
Probably engine or gas tank has to come out to get to it :(
In that case the hose sounds like a good idea LOL. Should flow freely. Nice boat!
 

kanada

Petty Officer 3rd Class
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Mar 15, 2011
Messages
76

Don S

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Re: Bringing 1978 470 to trouble free boating in 2011

Why are you using manual #8? you should be looking in #3

Here is one of the pictures in #3

attachment.php
 

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kanada

Petty Officer 3rd Class
Joined
Mar 15, 2011
Messages
76
Re: Bringing 1978 470 to trouble free boating in 2011

Thanks Don!

I triple checked that I got the right thermostat and put it in the right direction.

Water pump cover showed up today and I got confused.
Old water pump cover has a seal behind the water pump cover insert, new one does not.
I am looking at the manual and there is no mention of upper cover seal behind the insert only 2 oil seals in the base.

I am thinking previous owner installed it there by accident.
Since there is no point for the seal there - its water inside and exhaust+water outside the cover.

Or should there be a seal in the upper cover?

And I am not talking about the #41
http://www.mercruiserparts.com/Show...bnbr=80&bdesc=GEAR+HOUSING+ASSEMBLY,+COMPLETE

looks like #25 is installed between #30 and #31


thanks a bunch!
 

Don S

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Re: Bringing 1978 470 to trouble free boating in 2011

#25 fits in the base (#23) of the water pump, not in the upper pump housing (#30)

What are you using for a manual?
 

kanada

Petty Officer 3rd Class
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Re: Bringing 1978 470 to trouble free boating in 2011

Service Manual #3 for Engine #4 for outdrive.
I have 2 original paper books (all yellow from age) that cover everything except closed cooling on my 470.
Will snap a photo of books and water pump cover old anf new tonite.
 

kanada

Petty Officer 3rd Class
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76
Re: Bringing 1978 470 to trouble free boating in 2011

here is what I found in the upper impeller cover:

old.jpg

and here is the new replacement impeller cover.

new.jpg

Should there be a seal in the new upper water pump cover?
 

kanada

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Re: Bringing 1978 470 to trouble free boating in 2011

Anyone?
 

Don S

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Re: Bringing 1978 470 to trouble free boating in 2011

There is NOT supposed to be a seal in there. Just put the SS insert in and install it.
 

triggmarine

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Aug 19, 2011
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Re: Bringing 1978 470 to trouble free boating in 2011

the housing with the seal is most likely a '78 survivor made out of aluminum the replacements are plastic and the seal was eliminated as it really was never necessary
 

kanada

Petty Officer 3rd Class
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Mar 15, 2011
Messages
76
Re: Bringing 1978 470 to trouble free boating in 2011

Just to close the thread.... with what was the true cause....

Overheating issues improved. After thermostat & impeller replacement, temp only went up to 185 when cruising for a long time.
However..... when I went to drain the exchanger, since the temps had to dip to low 30 couple night back, I got antifreeze coming out.
At first I thought I undid the wrong bolt, but turns out that the heat exchanger is toast. its a 3" unit cirka '78
Scored a 4" unit for $200 of ebay. There is still plenty of fishing to do this year.

Starter died and got rebuild on one of the trips too.

So we have charging untouched from electrical side..... And bellows and shifting to complete the full refresh.

Kanada
 
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