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GregB

Common Causes for flooding

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GregB

Subject engine is a Briggs 16hp in a B series large frame.  Never had the engine running.  Had to replace the coil because the E-bay seller did not ship it with the external coil set-up.  Has good spark testing it grounded to the engine.  Both with the carb that was on it, and another known "good" carb, it floods and you can see gas in the area of the carb between the choke plate and where the air cleaner sits.

What should I be checking?

When you crank, it does not even sputter or try to fire on starting fluid?

 

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GregB

Yea I thought of that but was trying to see if there was anything less invasive.  Pull the motor I just installed, tin and flywheel...............shame there is not some kind of external timing mark to check static timing like on aircooled VW's.

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rockfangd

weak, or no spark is #1.

Plug or coil. Pull plug. Is it wet?

I am having the same problem as you. ALmost. Gas will come out of the carb when it floods

Bad float would cause issues as well but sometimes you would see it dripping from the carb when just sitting

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GregB

Changed plug last night, same results.

Pop'd the points cover, the points barely open and the movable side is sort of cocked.

Time for points and gap correctly and hope plunger behind points is not worn.

The manual says there is a way to time the coil, but it involves pulling engine and shroud.

Last resort.....................

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MARK (LI)

Sounds like some conflicting information...you say you have a good spark, but points are questionable...I am not positive, but I think that you can eliminate the points with a NOVA ignition

but I don't think that would cause flooding..and although you tried it with a second "known good" carb it sounds like a carb float problem in both carbs....coincidental, but possible

 

Does it continue to flood after you stop attempting to start it...or just while you are cranking it?...is there a fuel pump on this engine?

just trying to get some more data to help someone get a "click" in his head and recognize the problem

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GregB

My spark at the plug looked relatively strong and bright.  Since the points appear to be set to close together, and crooked also , I thought maybe it could be affecting timing.

I also replaced the coil this summer because the PO, did not supply the external coil.  There is a timing procedure for the coil bracket to the flywheel.  It looked OK so I did not mess with it.  Maybe I should have checked that further before I shrouded and installed the engine.

Only floods when cranking, does not leak otherwise like stuck float.

Even if I spray starting fluid into the cylinder, replace the plug, and try to start, it does not pop on the ether.

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MARK (LI)

Well...you need 3 things for engine to run:

1) Spark...sounds like you have it

2) Fuel...sounds like you have that also

3) Compression...may sound off base but you might consider doing a compression and  leak down test

 

Here is a link to a good explanation of each test and what you would hope to find out

http://www.dsmtuners.com/threads/compression-and-leak-down-testing.338152/

 

 

Edited by MARK (LI)

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GregB

I know, but if the spark is not timed correctly, no ignition right.

I can also check to make sure no stuck or limited travel valves.

 

I just need to repeat over and over "mechanical things will not upset me, mechanical things will not upset me,........"

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MARK (LI)

But with an engine out of time you should get some backfiring even if it won't start...or coughing back through the carb, or a dead spot when you turn the engine that will seem like the battery died at that spot

The Cam and crank timing is set when assembling the engine and can't really change once reassembled...the ignition timing is set with the "woodruff key" or flywheel key and although tedious removing shrouds it is not difficult to get to it and see if it is a problem....often it is necessary to pull the flywheel to determine without doubt that it has not been sheared at all...even a small nick can put it out of time

 

See if these videos help you at all

 

Edited by MARK (LI)

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MikeES

With the Briggs updraft carb, you can have gas running out of the carb and not have the engine flooded.   I have found that when I have issues starting a Briggs it ALWAYS points.   

My guess is points.  Clean and file the points or replace them get the gap at .020.   I have had "good spark", chased my tail until I clean and adjusted the points and Voila...she runs

.If your spark plug is not wet, it is not flooded

Also I have never been able to get a Briggs to fire on starting fluid, and with the updraft carb, I have always had to remove the spark plug and pour a little gas in the plug hole to get them to fire.

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Tom45

The video has some misleading information, especially the first of the four.  If you follow the Briggs shop manual, the coil mounting bracket position is set by using a test light or tester with the points set at .020.  If the mounting bracket cannot be shifted enough to get the arrows on it and the flywheel to line up, that is an indication that the cam timing is off a tooth.  

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MARK (LI)
51 minutes ago, Tom45 said:

The video has some misleading information, especially the first of the four.  If you follow the Briggs shop manual, the coil mounting bracket position is set by using a test light or tester with the points set at .020.  If the mounting bracket cannot be shifted enough to get the arrows on it and the flywheel to line up, that is an indication that the cam timing is off a tooth.  

But wouldn't a cam timing have been done when assembling the engine....can it "jump" a tooth somehow when running causing it to go out of time?

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Tom45

Yes, the cam timing is done when the engine is assembled.  It affects both the valve timing and points timing.  I do not think there is any way it can change other than disassembly of the engine.  

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GregB

Filed and adjusted points.  Couple of cranks it fired and ran smooth.  Now I have to run it and see if the rings re-seat.  It smokes on speed change, and start-up. wah

MikeES thanks..............

 

Edited by GregB

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