I recently bought a generator that uses a Briggs and Stratton 17hp Vanguard engine. Before purchasing the generator, it had not ran in several years. The fuel was stale and the oil needed to be replaced.

My DIY experience is extremely limited but I decided to work on it anyways. After replacing all of the gasoline, adding fuel cleaner and fuel stabilizer, I ran the generator for 10 minutes. It ran beautifully. I turned the generator off and then changed the oil.

At this point, I wanted to use some carburetor cleaner that I was recommended. I asked my neighbor if he could give me a hand with this part.

I tried to run the generator the next day. It ran fine for four minutes and then died. I started it again and it died after about ten seconds. I noticed that gas was actually pouring out of the exhaust. After a few more attempts, I brought my neighbor over to have a look at it again. When starting the generator for him there was a lot of white smoke and the engine immediately died. After further inspection, he determined that what he thought was the carburetor, was actually the fuel pump.

My neighbor says I should replace the needle valve and the fuel pump. He also thinks that the oil was too high (thus causing the white) smoke. I ordered/replaced the fuel pump and needle valve and then checked the oil to find that it was way too full and smelled of gasoline.

My next step is to flush the oil by repeatedly filling/emptying until I do not smell gas. I also plan on replacing some of the fuel lines that are in bad shape.

So my question is: could there be something else wrong with the engine that I am missing? Do I need to replace the carburetor float as well? Any tips would be much appreciated!

2 Answers 2


More than likely what the problem is, your float in the fuel bowl is shot. When the float is shot (ie: doesn't float correctly in the fuel), too much fuel is let into the carburetor and causes the exact issues you are talking about.

You may be able to get a new float and needle valve (very likely), but you may just be better off buying a new carburetor. There are two reasons I say this: 1) there may be more wrong with your carburetor than just the float; 2) the whole carburetor usually doesn't cost too much and is an easy replacement item.

As for the fuel pump ... I didn't think these smaller engines came with a fuel pump? Every small B&S engine I've seen works off of gravity feed for gasoline. Even if it does have a fuel pump, wouldn't it seem to you that having too much gas means the pump is working? The opposite would be true if it weren't.

If you haven't done so, you'll want to change out the oil in the engine before you do anything. Bad oil as you have may cause damage to the rings and bearings. You'll have to run fresh oil anyway, so might as well change it as soon as possible.

One other thing to mention. When you do get this fixed, install an inline fuel cut-off valve. When you finish using the generator, switch it to off while it's running and run the generator out of fuel (without a load on it). In doing so, the carburetor will be nearly if not completely dry. This will make for happier starting the next time you go to use the generator. Just make sure you turn the valve to "on" before you start to crank it ;-)

  • Thanks! That seemed to have done the trick. I'm still getting some white smoke, but I'll put up a new question for that. Besides the white smoke, the generator runs perfectly.
    – KJ Price
    Jul 16, 2015 at 22:32

I suspect you have bad rings on your piston, thus letting some oil to get past and into the combustion chamber producing white smoke as oil does when it's burned.

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