Trouble with my Vanguard Twin

Thanks guys... Well I got a stomach bug, back I am on track now... I have 40 PSI at the fuel line test port... upon key on, not running. Will try to test for pressure while / if it is running today. While I was at it I removed the injectors and tested them for electrical resistance, function and spray pattern... all looked extremely good. The filter on the tank vent did appear to be stopped up, or at least partially so... might get lucky! Cylinder jugs heads in engine in general was actually pretty clean under the covers, but I intended to clean it well before it goes back together. still need to check the tank screens.
Hammermechanicman said:
Jack's has it

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That's awesome! So here is the thing I did all my inspections and cleaned up the engine and put it back just enough I could run it with the fuel pressure gauge hooked up. It started and ran fine, no load. Fuel Pressure went immediately to 38 pounds... so I decided to stimulate some load, I kicked the blades on, fuel pressure immediately dropped to 15 pounds in the engine dies. As soon as the engine dies the fuel pressure pops back to 38 pounds. So I went through that three or four times and so I assume, Yep I need the high-pressure fuel pump.... and I said well one more test I can do is see if it will move itself with the blades off, it would not do that the other day, It stumbled and about killed the engine... did that a couple of times. Each time the fuel pressure would drop way down 10 or 15lbs. Then I tried it one more time and it worked! Fuel pressure dropped only 2 or 3 pounds and jump right back up to 38. I tried to several more times, worked fine so I kicked the blades on as well... worked fine held 38 or almost 40 lb. Something going on wonky with that fuel pressure... Man that's a great price on that pump. I appreciate the heck out of that link and info At that price I'll just buy one and put it on it. I don't quite have it all back together. I think I'll finish buttoning it up. Tryy mowing with it and just see... but I'm pretty sure I'm gonna go ahead and order that pump. Only other thing it might be is an electrical supply to the pump intermittent.... but after it falters it instantly returns to working. IDK. thanks so much again folks! Lunch is on me at the local Cafe if you are ever in Bell Buckle TN!


That wire to the HP pump is tiny, I'll take it off and inspect very closely, could be vibration has gotten to it...
 
What is the compression on this engine?

I’ve been reading you are working a probable fuel issue.

I read you checked the valve clearance but I did not see that you used a compression gauge to verify the compression. This is one of my first steps.

Basics are spark at the correct time, compression, and fuel.

I have seen individuals chasing fuel issues when it was actually compression and timing issues.

Please follow up with your solution for others to learn from in the future?
 
Can't check compression because of the automatic compression release... UNLESS... there is a work around I haven't heard of. According to my research B&S doesn't even specify a compression spec.
 
We can try this old school. Put thumb over spark plug hole and have someone crank the engine. Note: watch out for that spark plug wire and boot!

Did it blow your thumb off?
 
cparktd said:
Only other thing it might be is an electrical supply to the pump intermittent.... but after it falters it instantly returns to working.
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Check pump powers and grounds BEFORE buying any new parts. Do you have a solid 13+ volts DC at all times to the pump? Verify the pump ground is clean and tight too. Don't go any further until you do these tips. You can run a temp line from the battery both + and -. Make darn sure the pump itself is failing not the power or ground. Remember this mower bounces around all over town LOL.
 
slomo said:
Check pump powers and grounds BEFORE buying any new parts. Do you have a solid 13+ volts DC at all times to the pump? Verify the pump ground is clean and tight too. Don't go any further until you do these tips. You can run a temp line from the battery both + and -. Make darn sure the pump itself is failing not the power or ground. Remember this mower bounces around all over town LOL.
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The mower will run about 20 min then it starts stumbling and dies. If I hit it with starter fluid it runs. After cooling off it will run another 20 min. The ginuine Briggs fuel pump I ordered from Jacks for $331 was backordered on 3/29. They got it in today 4/6 so hopefully it will ship out to me today. I have literally spent zero $ on the mower it in ten years except for one deck belt, damaged when a stick caught in it, and regular service. Amazing machine. I'm OK with trying a new pump. I have inspected the pump electrical plug and wires, looks OK but I have not tested the voltage yet. The pump runs, but seems to be losing pressure, monitored with a gauge, that coincides with the engine stumbling. absolutely appreciate the replies and will let you know the outcome of the new pump.
 
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