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Discussion Starter · #1 ·
In the picture below...What is the part circled in red? (not a photo of my engine)


When I was bleeding my fuel lines i was not able to get fuel to flow passed this part (into the injector line) unless I loosened that circled part. I don't know why that was but once it was loosened I was able to get fuel to flow into the injector line and push out the trapped air.

Based on other bleeding procedures I have never heard this before and my manual doesn't outline it either.

Also on a side note...
Will Seafoam and anti-algae additives be filtered out by the fuel/water filter separator?
 

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In the picture below...What is the part circled in red? (not a photo of my engine)

When I was bleeding my fuel lines i was not able to get fuel to flow passed this part (into the injector line) unless I loosened that circled part. I don't know why that was but once it was loosened I was able to get fuel to flow into the injector line and push out the trapped air.

Based on other bleeding procedures I have never heard this before and my manual doesn't outline it either.

Also on a side note...
Will Seafoam and anti-algae additives be filtered out by the fuel/water filter separator?
I wouldn't think so, being liquid. However, any deposits or debris that the additives break free or partially dissolve will hopefully stay in the filter. I think some additives "absorb" water to be burned with the fuel. I know from my experience that this does:

Power Service Products is America's largest manufacturer of technologically advanced diesel fuel additives.

Paul T
 

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Over Hill Sailing Club
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On my 3GM there IS a bleeder up on the injector pump. It is partially hidden by the water hose. I would think the 1GM would have a bleeder in the same location?? Maybe you're not seeing it? The part circled looks like the fuel outlet from the injector pump. Actually it is probably the Inlet. The outlet to the injector should be the smaller diameter tube with a banjo fitting. If you can get fuel to the injector pump, the engine will start but that section of tubing, from filter to pump does get air-locked and needs to be bled or you can crank forever with no start.
 

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That's the high-pressure side of the fuel injection pump, the fuel line goes from there to the injector, the low pressure comes in on the side of the pump. You should bleed to the low pressure side using the manual pump (there is a bleed screw on the top of the filter and another on the banjo fitting on the injection pump), and then the high-pressure side by cracking the fitting at the injector and turning the engine over until no more bubbling.
 

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The accompanying pic on the original post is not visible on my browser for some reason. However, on the typical injection pump on the QM and GM series Yanmar engines the bleed screw on these injection pumps is on the inlet / low pressure side of the pump. Once the inlet side and piping/hosing between the lift pump and injector pump is "bled'' and clear of air and fuel is flowing to the injector pump ( all the fuel delivery system between the tank and the injector pump is free of air), such injector pumps and the remaining tubing all the way to the injectors rarely needs to be 'bled' as the high pressure from the injector pump will usually fill it and clear any air.

Rx: Rarely does one need to bleed air 'downstream' of the injector pump on most Yanmar engines. Just bleed the air 'to' the injection pump bleed screw and the pump pressure will then clear all the remaining air up to the injectors; although, you may have to wait a bit while the starter is turning the engine and the injector pump and downstream lines to the injectors are self-purging themselves with air and/or only a single cylinder is 'firing' and the engine is running 'very rough' until the other injectors and their supply tubing are fully purged of air.
 

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Discussion Starter · #7 ·
I actually stole the original picture from that Mark Corke Link above ;) I guess the part is nothing more than a thread adapter. I guess it confers from 1/2" threads on the engine block to flare threads for the injector tubing. I thought it might have been a check valve or something to keep fuel from flowing backwards and maybe it was stuck.

When I had bled the fuel system I started at the lift pump screw, then the injector pump screw, but that wasn't enough to get it fired. It wasn't until I cracked that thread convertor, that fuel would flow into the injector line.

On another note...
I started another thread about my fuel/water separator modification but I haven't gotten any comments gets. Could someone please tell me if this was a good idea or if I am asking for trouble...
http://www.sailnet.com/forums/diesel/161121-modifying-fuel-water-separator.html

Thanks,
Zac
 

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Over Hill Sailing Club
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That's what we are saying. There should be a bleeder screw just BEFORE the injector pump, on the low pressure side but after the filter bowl which has its own bleeder. If you can get fuel to the inlet of the injector pump, the pump will take it from there. At least that's the procedure on my 3GM. Once I get fuel up to the injector pump, the motor will kick right over. The nut you loosened is just a reducer of some sort.
 
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