Vanguard 16 hp running rough

1mk2

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I have a model 612 Grasshopper that I bought recently, if you look at some of my posts I give a little history on it and there are some photo's. I mowed several times with it and it mowed great but lately it has started to run rough, surging. So one day I took all the fuel lines off and made sure there was no stoppage and blew out the fuel pump also then put everything back and it ran smooth as silk. Now it is starting to run rough again and today I mowed about 8 passes and it stopped. I could turn it over and it would start but shut off in a few seconds. This time I took the fuel lines off and the fuel pump and blew them out and put a new gas filter on and it ran good but not the same power it did have. When I was finished mowing it was surging again but keep running without shutting off. Do you think it could be the fuel pump? This mower sat for a few years after the owner replaced the motor with a Vanguard 16 hp and was not able to get it running. Later the owner gave it to a mowing service for payment for their service and they found a loose wire on it and it ran. It has very few hours on it but it did sit for a time and don't know what that could have done. It ran so great at first going through high grass without a struggle and now I am having a problem and since I have used it and refueled it several times I know it is not stale gas and the air cleaner looks new, anyone have any ideas that I could check?

Thanks,

Mike
 

shiftsuper175607

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I have a model 612 Grasshopper that I bought recently, if you look at some of my posts I give a little history on it and there are some photo's. I mowed several times with it and it mowed great but lately it has started to run rough, surging. So one day I took all the fuel lines off and made sure there was no stoppage and blew out the fuel pump also then put everything back and it ran smooth as silk. Now it is starting to run rough again and today I mowed about 8 passes and it stopped. I could turn it over and it would start but shut off in a few seconds. This time I took the fuel lines off and the fuel pump and blew them out and put a new gas filter on and it ran good but not the same power it did have. When I was finished mowing it was surging again but keep running without shutting off. Do you think it could be the fuel pump? This mower sat for a few years after the owner replaced the motor with a Vanguard 16 hp and was not able to get it running. Later the owner gave it to a mowing service for payment for their service and they found a loose wire on it and it ran. It has very few hours on it but it did sit for a time and don't know what that could have done. It ran so great at first going through high grass without a struggle and now I am having a problem and since I have used it and refueled it several times I know it is not stale gas and the air cleaner looks new, anyone have any ideas that I could check?

Thanks,

Mike

Does it have a carburetor?

If so, it needs cleaning.
 

1mk2

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Does it have a carburetor?

If so, it needs cleaning.

Thanks, I didn't think of that because it is a engine with very little hours on it but it did sit for awhile and maybe the gas gummed up in it from sitting so long but I can't figure out why it ran so good then up till now. I will definitely check that and let you all know if that was the problem.

Mike
 
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I have a model 612 Grasshopper that I bought recently, if you look at some of my posts I give a little history on it and there are some photo's. I mowed several times with it and it mowed great but lately it has started to run rough, surging. So one day I took all the fuel lines off and made sure there was no stoppage and blew out the fuel pump also then put everything back and it ran smooth as silk. Now it is starting to run rough again and today I mowed about 8 passes and it stopped. I could turn it over and it would start but shut off in a few seconds. This time I took the fuel lines off and the fuel pump and blew them out and put a new gas filter on and it ran good but not the same power it did have. When I was finished mowing it was surging again but keep running without shutting off. Do you think it could be the fuel pump? This mower sat for a few years after the owner replaced the motor with a Vanguard 16 hp and was not able to get it running. Later the owner gave it to a mowing service for payment for their service and they found a loose wire on it and it ran. It has very few hours on it but it did sit for a time and don't know what that could have done. It ran so great at first going through high grass without a struggle and now I am having a problem and since I have used it and refueled it several times I know it is not stale gas and the air cleaner looks new, anyone have any ideas that I could check?

Thanks,

Mike

Mike I would put new fuel lines on the mower if it was in my shop. We have seen time after time that the inside of the fuel lines break down with time. This plugs either the filter, fuel line, or the carb eventually. I am with the other guys in that the carb needs cleaned now to. I would not have recommended it needing clean at first since you did run it for some time before it started having issues. Usually one knows right away whether or not the carb is plugged after starting it. Also be sure the tank is clean. Any restriction out of the fuel tank at all will cause any of said symptoms. I hope you are able to find a fast repair!!
 

1mk2

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Mike I would put new fuel lines on the mower if it was in my shop. We have seen time after time that the inside of the fuel lines break down with time. This plugs either the filter, fuel line, or the carb eventually. I am with the other guys in that the carb needs cleaned now to. I would not have recommended it needing clean at first since you did run it for some time before it started having issues. Usually one knows right away whether or not the carb is plugged after starting it. Also be sure the tank is clean. Any restriction out of the fuel tank at all will cause any of said symptoms. I hope you are able to find a fast repair!!

Thanks so much for the reply, the first thing I did when I started noticing a problem was to take off all gas lines and check them and they are in very good condition and fully opened. You have me thinking now about a line that is in the fuel tank its self that feeds the gas to the fuel pump that I didn't think to check so I will look at this line and then the carb. I am the care giver for both my parents which keeps me very busy, they are both in their 90's but am hoping to get a chance to look at the Grasshopper Saturday.

Thanks to everyone that has replied it has given me some good ideas of things to check. This mower did not have a fuel filter when I bought it and I have just put one on the last time I mowed so something could have gone though and clogged a jet. I will post a new thread when I find and correct the problem. Again thanks so much.

Mike
 

bertsmobile1

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You get this type of problem when grass clippings & other floating debris gets drawn into the fuel tank outlet.
Quick & dirty test is to rig up an alternative tank and when the mower stops, quickly swap the connections to the fuel pump with the alternative tank.
Problem goes away then it is tank cleaning time.
Golf T's make perfect plugs for fuel lines.
 

1mk2

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Mike I would put new fuel lines on the mower if it was in my shop. We have seen time after time that the inside of the fuel lines break down with time. This plugs either the filter, fuel line, or the carb eventually. I am with the other guys in that the carb needs cleaned now to. I would not have recommended it needing clean at first since you did run it for some time before it started having issues. Usually one knows right away whether or not the carb is plugged after starting it. Also be sure the tank is clean. Any restriction out of the fuel tank at all will cause any of said symptoms. I hope you are able to find a fast repair!!

I have taken off all fuel lines and am going to replace them, I would also like to clean the carb. How would you suggest cleaning the carb, spray carb cleaner into it or take it off and clean everything? I believe there is one jet but was pulled away yesterday before I got a chance to find where it was located. I do have the top of the carb off and the float looks good.

thanks,

Mike
 
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I have taken off all fuel lines and am going to replace them, I would also like to clean the carb. How would you suggest cleaning the carb, spray carb cleaner into it or take it off and clean everything? I believe there is one jet but was pulled away yesterday before I got a chance to find where it was located. I do have the top of the carb off and the float looks good.

thanks,

Mike

Mike If it was the my shop I would take it off the engine, pull the bowl off and clean the main jet (should be easily seen with the bowl off). It is located in the center of the float. Also while you have the carb off, flip it upright and move the float up and down and watch the needle move. If it hangs any what so ever you will need to replace it. If it moves freely it is good to go. Make sure the carb is pretty level when you do this. Carb cleaner is fine to use. I use a ultra sonic cleaner and blow them out with forced air. Hope this helps!
 
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