Hey I made a post here a couple of weeks ago about my 17hp vtwin briggs and stratton shooting gas back up through the carb. Well I got the motor torn down and seem to be :confused:. None of the valves are bent. That was determind the culprit but its not. There is some carbon build up though. Could that be the problem? Also is there any way to ajust the valves on this motor? Its a horazantaly opposed v-twin.

BRIGGS AND STRATTON 17hp v-twin
model~ 42A707
type~ 2238 E1
code~ 01012195A

Even if you had a valve not seating for whatever reason I would doubt that is the problem. To set the valves involves removing the valve and grinding it on the stem end to proper clearance. A compression check would tell all in that area. I would look to a malfuctioning carb float or needle seat problem. Since this carb has a vacuum pump fuel getting by the needle when its not supposed to be can only happen when the engine is running for the most part. Start the engine, I assume it will be sloppy with gas, pich off the fuel line with a clamp if you don't have a valve. Let the engine run until it runs out of gas. It should clear up and run well in the moments before it dies. That will almost surely show a fuel/carb problem rather than valves etc.

mike

Thanks I will have to look into that. Before I tore it down it would run but very rough and misfireing then would die after about 30 seconds or so of running. One side was running richer than the other and gas would be litterally spitting out the carb.

A valve problem or loose seat on this engine can indeed cause fuel to spit back out of the carburetor, since one side is working ok and the engine is running. If one side has a problem with the intake valve then back pressure can be fed back up through the intake manifold and cause fuel to splash up out of carburetor.

Also this is an opposed twin not a V-Twin

Oh. Thanks for the correction. What would it take to reseat a valve?

That depends on what the specific problem with the valve is and if there even is a problem with your valves. If the valve seat has come loose in the engine block, this may not even be repairable.

The first thing you need to do is determine if in fact the problem is with the valves. To do this you should as previously suggested do a simple compression test. If you find that one of the cylinders is very low on compression, then remove the head on that side and visually inspect the valve operation and condition of the valves and seats and go from there.

I have already torn down the engine. Looking at the valves on the problem side visually look good but It is soaked with gas. This includes the sparkplug which does not fire.

its flooding??

no its spitting gas out the carb

i mean the plug, its supposed to be black , not soaked with gas. is it getting spark?

I know that but its soaked in gas

bump...

No more help avalible?

Have you checked the dead side with a spark tester to see if you are getting spark to the plug?

Yes I am.

Getting spark but the spark plug does not fire?

Try another plug.

I already did

Have you checked the valve clearance on the side thats not working?

How can you? I looked and looked and found no way to do it. How do you?

There is an access plate that is held on with a couple of screws, after you remove the cover you can use a gauge to check for proper clearances.

There are two openings on the front of the engine and all they show are the springs.

Well that what you see most of, but the end of the valve stem and the lifter are there as well. There is a retainer holding the spring to the valve stem, under that is where you will find the lifter. With the piston on TDC on the compression stroke, measure the clearance between the lifter and the valve stem end with a feeler gauge.

That depends on what the specific problem with the valve is and if there even is a problem with your valves. If the valve seat has come loose in the engine block, this may not even be repairable.

The first thing you need to do is determine if in fact the problem is with the valves. To do this you should as previously suggested do a simple compression test. If you find that one of the cylinders is very low on compression, then remove the head on that side and visually inspect the valve operation and condition of the valves and seats and go from there.
It is the valve. How do I reseat it?

Are you talking about the valve seat? or the Valve?

Wait is it possible that it jumped the timing chain or is there none on this motor?

No timing chain, if it's ever been apart the timing could have been set wrong, otherwise probably not.

Alright... I took another look and found that there is some carbon deposits in the intake. So I am assuming that I have a seal problem correct?

over head valve ain't it ? 17,hp v-twin , 2001 , is it filling the crank case with fuel ? are you grounding the plug to the engine ? is the engine rolling over fast ? also remember if it don't fire there are (or should be ) safety switches that will keep it from firing . i take the wire off the coil to eliminate the switches when checking fire , if thats the problem at hand , you can just remove the one thats on the shroud but it could be dead shorting from the coil (module) up to the shroud, as far as the problem with the valves you need to do a compression test ..... that will save you time money and headaches ,
also how did it screw up , (probably the most important question ) did you go out to start it and wont start ? hit something . was it parked in a nice warm garage where mice will be mice . was power ran to the coil , where are you @ on it now ?

Its still towarn down. I will do a compression test. I am getting spark but its not fireing on the one side.