Can not get Tecumseh BVS/Vantage to run smooth

XGamer223

Active Member
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Sep 13, 2016
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Hello folks,
I can not get my BVS153/Vantage engine to run smoothly.
It not that it revs up and down and such governor issues, it's more like constant smaller misfires and non consistent running. No matter low or high throttle, it always has that issue. It doesn't bog down when under load, or anything. Also, what I noted is that when I give it more throttle, but in a quick manner, it would over-rev and then drop down to the normal speed (not sure if it matters, but I never had that issue before).

Carb is an adjustable Dellorto type, but it originally came with a non-adjustable one, both mixture-wise and thrrotle-wise. Never could get it to run with the orignal carb as it was full of something as it stood for a long time.

I did try adjusting it, finding the perfect spot but it has no meaning whatsoever, as going too high or too low just makes it bog or run very badly, so the mixture screw doesn't do much here. Also, when it's a cold start, it will surge for half a minute.

Did replace the sparkplug with what the factory suggests, and I even think it made it a bit worse. No matter if the air filter is on or not. New intake-to-intake-pipe gaskte was put on.
Only thing lef to do is to clean the carb, but it was taken off of a working mower with the same specs, and it ran good when it was on it.
What could it be?

(there are 3 videos)
 

Rivets

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I have a couple of questions. Are you sure that the carb we are seeing is an adjustable carb? Looks to me like you have an idle jet on the side of the carb, not an adjustable needle. Second, can you tell us if you have a points/condenser or CDI ignition system? Third, when you post back please include all numbers from the ID tag. I’m assuming you are in Europe as very few of the Vantage engines were sold in the USA.
 

XGamer223

Active Member
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I have a couple of questions. Are you sure that the carb we are seeing is an adjustable carb? Looks to me like you have an idle jet on the side of the carb, not an adjustable needle. Second, can you tell us if you have a points/condenser or CDI ignition system? Third, when you post back please include all numbers from the ID tag. I’m assuming you are in Europe as very few of the Vantage engines were sold in the USA.
Hi and thanks for the answer!
Never gave it any thought... a screw for me means it's adjustable, my bad. See the images, hope they help.
The ignition is a simple magneto directly tied to sparkplug, nothing else.
Sure I'll post the ID tommorow, couldn't make it yet. Also, it doesn't mean too much as the engine was swapped before, but it's a generic BVS153 motor (now a Vantage, but they're 99% the same but with lower quality, lol).

Some guides tell me that the screw under the bowl is the adjustment screw, but here it does nothing, or someone just intentionally covered it. Not really sure about it.
 

Rivets

Lawn Royalty
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That carb has no adjusting screw on the bottom. The bolt on the bottom holds the float bowl in place and contains the high speed jet. The one on the side contains the idle jet. Both will become plugged (especially when fuel is allowed to sit ing the carb for an extended period of time, and may need to be cleaned.
 
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