You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Export thread
Briggs 303777 no longer starting, fuel problem?
#1
F
fowl_language
F
fowl_language
Hello all, I hope someone can help me resolve this issue. I have a vanguard 16hp model number 303-777 motor manual found here:https://www.briggsandstratton.com/eu/en_gb/support/results/_jcr_content/par/productmanuallisting.downloadmanual.303777000701_IPLURL_LO.pdf.html
The motor is on a Troy-bilt Hydro 16 that I bought at an estate auction last year. The mower had been sitting for quite some time in a shed and had a community of mice move into every available space around the engine. The first thing I did last year was rip everything apart and blow out/shop vac all nesting material down to the bare block. I then reassembled everything and the engine was running fine until this winter. I now cannot get the motor to fire on gasoline alone. It will fire right up on a shot of modern starting fluid and will continue to run if gasoline is sprayed into the carb input.
It will not run on just gasoline from the fuel pump. This model has a (compression fuel pump?) (fuel pump hooked up to the valve cover supplying fuel pressure when turned over). I have checked the fuel pump and it spits gasoline when the engine cranks. After attempting to start and disassembling the carburetor the bowl is full of fuel.
I originally thought the main jet or something in the carb was clogged so I ran the carburetor in my ultrasonic cleaner with 50/50 pin-sol and water then washed it off and blew it dry with compressed air. resembled everything and the same thing is happening it runs on starting fluid or carb cleaner/aerosolized gas but not the fuel line. I cannot get the main jet to rotate out of the carburetor (stuck) for full disassembly so I thought the next best thing would be ultrasonic cleaning. I have ran wire through all the jets I can access and they are free of obstruction.
I have tested the fuel shut off solenoid separate from the carburetor and it will not actuate (12 volts), but I do not think this is my problem because the pin is not actuating upwards, it is stuck in the down position. The solenoid in this position allows for gasoline to pass through to the main jet throat. Unless this is not correct, please let me know! I have tested this by pouring gas in the pin hole of the solenoid and it comes out the side holes by the threads. I would think if it was stuck in the closed position that it would not allow for gas to pass through the holes in the "closed" condition.
I would just buy a replacement carburetor for this engine but everything on the engine has been discontinued, finding parts for it has proved impossible. I was lucky and got the last starting ring gear in existence early last year but anything fuel related is sold out and no longer produced.
The compression on the engine is strong you can't crank the flywheel by hand and the carb is audibly "sucking" air with every rotation. Any help on this would be greatly appreciated I am at my wits end with this thing and I hate to scrap a near perfect condition hydro mower just because I can't work out a carburetor problem.
The motor is on a Troy-bilt Hydro 16 that I bought at an estate auction last year. The mower had been sitting for quite some time in a shed and had a community of mice move into every available space around the engine. The first thing I did last year was rip everything apart and blow out/shop vac all nesting material down to the bare block. I then reassembled everything and the engine was running fine until this winter. I now cannot get the motor to fire on gasoline alone. It will fire right up on a shot of modern starting fluid and will continue to run if gasoline is sprayed into the carb input.
It will not run on just gasoline from the fuel pump. This model has a (compression fuel pump?) (fuel pump hooked up to the valve cover supplying fuel pressure when turned over). I have checked the fuel pump and it spits gasoline when the engine cranks. After attempting to start and disassembling the carburetor the bowl is full of fuel.
I originally thought the main jet or something in the carb was clogged so I ran the carburetor in my ultrasonic cleaner with 50/50 pin-sol and water then washed it off and blew it dry with compressed air. resembled everything and the same thing is happening it runs on starting fluid or carb cleaner/aerosolized gas but not the fuel line. I cannot get the main jet to rotate out of the carburetor (stuck) for full disassembly so I thought the next best thing would be ultrasonic cleaning. I have ran wire through all the jets I can access and they are free of obstruction.
I have tested the fuel shut off solenoid separate from the carburetor and it will not actuate (12 volts), but I do not think this is my problem because the pin is not actuating upwards, it is stuck in the down position. The solenoid in this position allows for gasoline to pass through to the main jet throat. Unless this is not correct, please let me know! I have tested this by pouring gas in the pin hole of the solenoid and it comes out the side holes by the threads. I would think if it was stuck in the closed position that it would not allow for gas to pass through the holes in the "closed" condition.
I would just buy a replacement carburetor for this engine but everything on the engine has been discontinued, finding parts for it has proved impossible. I was lucky and got the last starting ring gear in existence early last year but anything fuel related is sold out and no longer produced.
The compression on the engine is strong you can't crank the flywheel by hand and the carb is audibly "sucking" air with every rotation. Any help on this would be greatly appreciated I am at my wits end with this thing and I hate to scrap a near perfect condition hydro mower just because I can't work out a carburetor problem.
#2
B
bertsmobile1
B
bertsmobile1
Pull the carb off but leave the fuel line on.
Turn it sideways and blow air ( low pressure ) through the carb with the ignition turned on >
Note the fire risk here.
You should get a nice mist of fuel coming out the engine end.
With the ignition off there should be no fuel mist, if the shut off solenoid is working.
Did you pull the main jet out & check it was clean, and the same for the emulsion tube, paying particular attention to the cross drillings.
Turn it sideways and blow air ( low pressure ) through the carb with the ignition turned on >
Note the fire risk here.
You should get a nice mist of fuel coming out the engine end.
With the ignition off there should be no fuel mist, if the shut off solenoid is working.
Did you pull the main jet out & check it was clean, and the same for the emulsion tube, paying particular attention to the cross drillings.
#3
I
ILENGINE
I
ILENGINE
Like Bert I am suspecting fuel solenoid on the bottom of carb bowl. if you turn the key on and off you should be able to hear it click as it opens and closed with the key being turned on and off.
#4
F
fowl_language
Thank you for the response, I tested the fuel shut off solenoid with 12v and it does not actuate seems to be shorted out. Although the pin is retracted and stuck there. Doesn't that mean that the fuel is not shut off?
If that is the case then the engine should get gas, correct?
My hesitation to buy a new one is the cost of a new Solenoid seems like the going rate for them is $100 USD, I would hate to buy one and it doesn't solve my problem. I will take the main jet out as well as the tube and see if they can be cleaned up. The main jet seems to be stuck in the throat though so I will have to try a few different ways of loosening it.
F
fowl_language
Like Bert I am suspecting fuel solenoid on the bottom of carb bowl. if you turn the key on and off you should be able to hear it click as it opens and closed with the key being turned on and off.
Thank you for the response, I tested the fuel shut off solenoid with 12v and it does not actuate seems to be shorted out. Although the pin is retracted and stuck there. Doesn't that mean that the fuel is not shut off?
If that is the case then the engine should get gas, correct?
My hesitation to buy a new one is the cost of a new Solenoid seems like the going rate for them is $100 USD, I would hate to buy one and it doesn't solve my problem. I will take the main jet out as well as the tube and see if they can be cleaned up. The main jet seems to be stuck in the throat though so I will have to try a few different ways of loosening it.
#5
F
fowl_language
Thanks for the help, I will try to get the main jet out of the throat but when I tried earlier I was bending the brass instead of getting the jet to unscrew, I will give it another go after I had it in the ultrasonic maybe something loosened up.
The solenoid is stuck in the down position and shorts out every-time I hook it up to 12v negative on the chrome part, positive on the lead. But it is stuck down so I would think that fuel is getting to the main jet, unless I am thinking of that wrong?
F
fowl_language
Pull the carb off but leave the fuel line on.
Turn it sideways and blow air ( low pressure ) through the carb with the ignition turned on >
Note the fire risk here.
You should get a nice mist of fuel coming out the engine end.
With the ignition off there should be no fuel mist, if the shut off solenoid is working.
Did you pull the main jet out & check it was clean, and the same for the emulsion tube, paying particular attention to the cross drillings.
Thanks for the help, I will try to get the main jet out of the throat but when I tried earlier I was bending the brass instead of getting the jet to unscrew, I will give it another go after I had it in the ultrasonic maybe something loosened up.
The solenoid is stuck in the down position and shorts out every-time I hook it up to 12v negative on the chrome part, positive on the lead. But it is stuck down so I would think that fuel is getting to the main jet, unless I am thinking of that wrong?
#6
F
fowl_language
It looks like the main jet is pinned in to the throat, I know it probably is not but it won't budge at all I'll try a couple different tricks.
F
fowl_language
Pull the carb off but leave the fuel line on.
Turn it sideways and blow air ( low pressure ) through the carb with the ignition turned on >
Note the fire risk here.
You should get a nice mist of fuel coming out the engine end.
With the ignition off there should be no fuel mist, if the shut off solenoid is working.
Did you pull the main jet out & check it was clean, and the same for the emulsion tube, paying particular attention to the cross drillings.
It looks like the main jet is pinned in to the throat, I know it probably is not but it won't budge at all I'll try a couple different tricks.
#7
R
Rideau1
R
Rideau1
https://www.lawnmowerforum.com/show...-Jet-hard-to-remove?highlight=vanguard+303777
I have the same engine (actually I have two)and had the same problem to get the main jet out as you have. I searched back and found my post and the many help full suggestions from knowledgeable people here. I bought the new jet from my dealer. Bye-the-way, I soaked my jet with PB Blaster for a day or two before a tried to remove it. See my post (link above)
As far as the solenoid goes, I bought a fuel bowl screw to replace the solenoid. I wouldn't spend big money on a solenoid. I don't have the B&S part number for the bowl screw handy but will try to find it this weekend. The only reason for the solenoid is to prevent backfire/bang when the engine is switched off. I idle my engine for a few seconds before switching off and it works like a charm.
Another issue I had was that the bowl gasket fell part so that had to be replaced.
Great engine. Good luck.
Gil
I have the same engine (actually I have two)and had the same problem to get the main jet out as you have. I searched back and found my post and the many help full suggestions from knowledgeable people here. I bought the new jet from my dealer. Bye-the-way, I soaked my jet with PB Blaster for a day or two before a tried to remove it. See my post (link above)
As far as the solenoid goes, I bought a fuel bowl screw to replace the solenoid. I wouldn't spend big money on a solenoid. I don't have the B&S part number for the bowl screw handy but will try to find it this weekend. The only reason for the solenoid is to prevent backfire/bang when the engine is switched off. I idle my engine for a few seconds before switching off and it works like a charm.
Another issue I had was that the bowl gasket fell part so that had to be replaced.
Great engine. Good luck.
Gil