Antisyphon valve bad?

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Renken89

Seaman Apprentice
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Aug 9, 2013
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Re: Antisyphon valve bad?

Also it seems there is no pick up in my tank. Are they built into the tank by chance?
 
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Renken89

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Messages
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Re: Antisyphon valve bad?

Low WOT. Was having bogging and shut off problem. After cleaning the fuel pump and changing all filters the bogging and shut off stopped. Only to leave me with a low WOT
 
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Renken89

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Messages
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Re: Antisyphon valve bad?

The valve itself is unrestricted. Flows cleanly. Along with the fuel tank vent.
 
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Renken89

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Re: Antisyphon valve bad?

Another retired guy said:
You say the valve is flowing freely, so no problems there. Check this link to Don S sticky at the top of this forum, for possible causes of low WOT

http://forums.iboats.com/mercruiser...ives/list-possible-causes-low-wot-295070.html
Click to expand...

Yes sir that's what I've been working off of.
New ethanol free fuel
Same prop as before when boat was operational
Antisyphon clear, apparently do not have a removable pick up line
Oil level checked, will be changed tomorrow
No growth
Same drive and ratio as before
Arrestor looks clean, does not change performance if removed. Will clean to make sure
How would I check exhaust flap? I exhaust moves through bellows and prop does this allow me to assume the flapper/shutters work correctly?
Will check compression..
Same carb.. May need a rebuild although one was just performed 2 years ago it coils be compromised due to the amount of filth in the fuel pump
Checking pump pressure and vacuum tomorrow
No over load
Engine temps good
How do I make sure my linkage is correct and that flappers open fully? Although boat was operational with same setup before.

All my problems are also under load. No idle issue.
 
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Another retired guy

Ensign
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Jun 17, 2012
Messages
940
Re: Antisyphon valve bad?

Sounds like the fuel system was dirty before you cleaned/replaced things, so, number one suspect now is the carb. As you say, it may have been compromised by the filth in the fuel system.
 
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Renken89

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Messages
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Re: Antisyphon valve bad?

image.jpg

This is the sediment I found going from the tank straight to the fuel pump. Looks like rust. Apparently the steel tank is rusting from the inside out. Just purchased a fuel/water separator the other day. Looks like ill also be getting a new tank and fuel pump to go with it! As far as cleaning the carb goes. Will it need to be rebuilt or should a thorough cleaning be enough?
 
A

Another retired guy

Ensign
Joined
Jun 17, 2012
Messages
940
Re: Antisyphon valve bad?

I'm not a carb expert so don't know where the line is between rebuild and thorough cleaning. To clean it, some disassembly will be required, so some new gaskets are needed at least.
Any carb knowledgeable people ready to jump in here?
 
Grub54891

Grub54891

Admiral
Joined
Jun 17, 2012
Messages
6,147
Re: Antisyphon valve bad?

Just rebuild it,you will more than likely need the gaskets anyway. Not to hard to do,just make shure its clean-clean-clean!
The kit should have new needle/seat and all gaskets,check balls and accelarator pump piston.you will need to get the basegasket seperatly.
There are vids up top in the stickys,check them out. For the most part,if nobody has messed with the linkages tgey are normally set properly,but I always check em anyway. Float hight is real important!
Grub
 
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