Merc 470 howling noise

J

jfgln

Cadet
Joined
Sep 19, 2009
Messages
22
Hello, I was looking at a boat today that is powered by a Merc 470. When first started there was a howling noise coming from the engine. The owner stated that he was told that this noise was coming from the oil pressure relief valve. The noise did go away after 5 min or so.

Is this something to be concerned about? What is the fix?

Thanks
 
S

sdoomaha

Petty Officer 3rd Class
Joined
Oct 6, 2008
Messages
94
Re: Merc 470 howling noise

Do a search on 470s on this site. There is a lot of good information. The consensus and from my experience as well...a 470 is an engine that needs lots of TLC.

My 470 has never had a howling noise....if there is with the one you are looking at, something is wrong and would need to be fixed. 470s are not the ideal powerplant...and one with an undiagnosed problem is twice as scary.

I'd move on and not consider the purchase.

Best of Luck.
 
J

jfgln

Cadet
Joined
Sep 19, 2009
Messages
22
Re: Merc 470 howling noise

I don't think I will buy the boat, but I am still curious what would cause this noise. The owner said engine was new in 2000 and has always howled a bit at start up.

I also wonder if this engine has enough power for the boat. It an Olympic Hardtop 23'. Nice looking boat, but the noise scares me.
 

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J

jtybt

Senior Chief Petty Officer
Joined
Aug 5, 2009
Messages
730
Re: Merc 470 howling noise

Howling from the engine or drive?

Good idea you passed on the purchase...way under-powered.
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,514
Re: Merc 470 howling noise

I don't think I will buy the boat,
Click to expand...

Ayuh,... Good,... Don't....
The 470 is a motor you Don't want to own, under Any circumstances...
 
B

blueagletalon

Seaman
Joined
Aug 6, 2009
Messages
67
Re: Merc 470 howling noise

i have a 470 on my 19 foot thompson. i love the engine. i have had some problems with it but nothing major. i would buy another boat with this engine. no matter what you buy people are going to give their opnions about it.
 
Bondo

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,514
Re: Merc 470 howling noise

i have had some problems with it but nothing major.
Click to expand...

Ayuh,... Just wait til you need a part with the part # NLA,... There's Alot of 'em...
 
zbnutcase

zbnutcase

Commander
Joined
Sep 19, 2009
Messages
2,055
Re: Merc 470 howling noise

They would have been 10 times the engine if they included a balance shaft and a real alternator...'nutcase
 
G

guyaverage

Petty Officer 2nd Class
Joined
Aug 4, 2008
Messages
101
Re: Merc 470 howling noise

The howling from the oil pressure relief valve is a known issue. Mine used to do it all the time when I first got it, but has not done it for the last couple seasons.
 
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