496HO Blowby
08-01-2008, 01:57 PM
#41
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wow, that is great news beacuse the water we boat on here (northwest of chicago) is pretty muddy and these brass pumps aren't cheap. Luckily I found a guy selling these brand new takoffs for $150.00 each. The rear plate of the pump (that has the nipple on it) is different that the ones he was selling, so I just took a fly cut on my existing ones and they bolted right on.
08-01-2008, 02:55 PM
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[QUOTE=Naughty Kitty;2629604]Thanks for the input Ray. If the respected builder (PowerSource) in my area had not been so responsive, my next call was going to be to you. I don't believe it was detonation as the other 7 pistons all look good with no signs of peening on the head. so this points to the injector, which we will look closer at this week.
To prevent this problem from re-occuring in this or the other motor, can someone recommend a decent fuel additive to clean injectors?
I recommend and use the AMSOIL PI, it does a wonderful job on fuel injectors for both boats and vehicles.
http://www.amsoil.com/storefront/api.aspx
To prevent this problem from re-occuring in this or the other motor, can someone recommend a decent fuel additive to clean injectors?
I recommend and use the AMSOIL PI, it does a wonderful job on fuel injectors for both boats and vehicles.
http://www.amsoil.com/storefront/api.aspx
08-04-2008, 07:13 AM
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[QUOTE=07DominatorSS;2642287]
Thanks Dom, based on others recommendations I have been using Sea-Foam in the tanks. The one trick I wanted to try this weekend was to remove the water sepparator filters, pour out half the fuel and top off with sea foam then spin back on. However the filter are on so tight, I am going to destroy them in the process of removal and didn't have replacements with me this weekend.
Thanks for the input Ray. If the respected builder (PowerSource) in my area had not been so responsive, my next call was going to be to you. I don't believe it was detonation as the other 7 pistons all look good with no signs of peening on the head. so this points to the injector, which we will look closer at this week.
To prevent this problem from re-occuring in this or the other motor, can someone recommend a decent fuel additive to clean injectors?
I recommend and use the AMSOIL PI, it does a wonderful job on fuel injectors for both boats and vehicles.
http://www.amsoil.com/storefront/api.aspx
To prevent this problem from re-occuring in this or the other motor, can someone recommend a decent fuel additive to clean injectors?
I recommend and use the AMSOIL PI, it does a wonderful job on fuel injectors for both boats and vehicles.
http://www.amsoil.com/storefront/api.aspx
Thanks Dom, based on others recommendations I have been using Sea-Foam in the tanks. The one trick I wanted to try this weekend was to remove the water sepparator filters, pour out half the fuel and top off with sea foam then spin back on. However the filter are on so tight, I am going to destroy them in the process of removal and didn't have replacements with me this weekend.
08-04-2008, 09:54 AM
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Odd that only ONE piston was messed up while the other seven were fine. Usually if you had bad fuel more would look like your #1. A bad injector could be intermittent or the wire going to it could be faulty and not necessarily kick out a code.
Don't forget these engines are mass-produced for heavy-duty trucks and marinized by MerCruiser. They would be much more expensive if Merc had to tear them down and put in better pistons. (Which would still fail if you had a bad injector.).
Don't forget these engines are mass-produced for heavy-duty trucks and marinized by MerCruiser. They would be much more expensive if Merc had to tear them down and put in better pistons. (Which would still fail if you had a bad injector.).
08-05-2008, 06:40 AM
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I had a friend come out from Stateline Marine on Saturday to run diagnostics on both motors via Diacom's Marine software. We ran both motors through a series of lake runs and RPM ranges and were unable to identify any abnormalities.
I've attached the reports below in case someone more familiar with these reports might find something out of the ordinary.
Starboard Motor (burned hole in piston @ ~200 hours, now fresh long block):
Starboard Motor Report
Port Motor (no known problems and ~225 hours old):
Port Motor Report
I've attached the reports below in case someone more familiar with these reports might find something out of the ordinary.
Starboard Motor (burned hole in piston @ ~200 hours, now fresh long block):
Starboard Motor Report
Port Motor (no known problems and ~225 hours old):
Port Motor Report
Last edited by Naughty Kitty; 08-05-2008 at 06:47 AM.
08-05-2008, 06:56 AM
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If you notice in your pictures and on the motor, the fuel line inlet bard to the cool fuel system at the primary suction pump looks to be a 3/8" line size, which has about a net 1/4" inside opening at best.
The bottom line is make sure the fuel feed lines from your fuel tanks to the 496 fuel pump inlet location are 1/2" size on both lines and fittings and that if your boat has anti-siphon fittings at the fuel tank, that they are also 1/2" size instead of the 3/8" size we see on most boats, even those with 1/2" fuel lines. Remember its not the OD size of the line that counts, its the ID size that flows the fuel!!!
The bottom line is make sure the fuel feed lines from your fuel tanks to the 496 fuel pump inlet location are 1/2" size on both lines and fittings and that if your boat has anti-siphon fittings at the fuel tank, that they are also 1/2" size instead of the 3/8" size we see on most boats, even those with 1/2" fuel lines. Remember its not the OD size of the line that counts, its the ID size that flows the fuel!!!
The fuel lines that Warlock used are clearly marked "3/8 ID" and for what it's worth have an OD diameter about 9/16". I would have to think the 3/8" ID is an accptable size as all the rigid lines Mercruiser uses appears to less than 1/2" OD, which would make the ID of those approximately 3/8" ID. I haven't checked to see if I have anti-siphon lines on the tanks yet, but will this weekend.
As always, your suggestions are always welcomed.
-Jeff
Last edited by Naughty Kitty; 08-05-2008 at 07:14 AM.
