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Need help on B-S V-twin

#1

G

Goober11

New to the form just signed up today. I have a Briggs & Stratton 20 hp V- Twin Model # 407777-0268E1 Code 030102YG. The engine will start up a run fine (hot or cold). It starts to break down( popping through the exhaust) an miss about 60% throttle or when you engage the blades. It is not bad enough that I can not cut grass but I know it is not right. I have adjusted the valves, new plugs, air filter, fuel filter. The hose from the valve cover to fuel pump was bad replaced that also. Thought that was the problem but still popping through the exhaust. With engine running I can pull Left plug wire(oil filter side) off and there is no change to the Eng. pull right plug wire on Eng. it makes a big difference in running. PLEASE HELP.


#2

L

Luffydog

Check for water in the gas. Also get a lighted spark tester and check for good spark. You problem maybe fuel related meaning water or time to clean the carb. After looking at your carb it's a double barrel carb prob not getting the proper amount of fuel at times or none at times.


#3

G

Goober11

Thanks for reply. Will check the items you talked about tomorrow it is 10:25 Friday night here. I did pull the top cover off an the flywheel was full of rust cleaned everything up. set gap in coils. Did run better but still not right. will look at carb. tomorrow . I can pull the choke out some when running and it does not help.


#4

cpurvis

cpurvis

If pulling the left plug wire makes no difference in the way the engine runs, then that cylinder is dead.

It could be something as simple as a bad spark plug or plug wire.

Or it could be a bad ignition coil.

Or worse, it could be a broken pushrod or a valve guide that has moved in the head.


#5

L

Luffydog

yes if you pulled the choke and no improvement i would say test the spark make sure it is good sounds more like it has a dead hole.


#6

G

Goober11

I think I have a dead cyl. also. I did take a compression test on it. Not sure how accurate it would be on that engine. Left was 100, right was 75. I do not have a spark tester but when I pull the plug wire off when the engine is running it will throw a good spark. I do not have a leak tester my have to pick one up to help me diagnose the problem. I am new on working on small engines. Worked as a mechanic for 45 years mostly on diesel road tractors. I am trying to learn about small engines to help me save some money and there are not to many shops around here that i would want to take it to. Sorry to say.


#7

G

Goober11

I did a leak down test on Motor. It failed. Will have to pull down an see what it needs. Thanks for all the good info.


#8

Boudreaux In Eunice La.

Boudreaux In Eunice La.

Take the suspect head off and then check for the valves and pushrods..... No need to get into the whole engine.......

Let us Know Mon Ami ~!~!


#9

T

Tinkerer200

Boudreaux In Eunice La. said:
Take the suspect head off and then check for the valves and pushrods..... No need to get into the whole engine.......

Let us Know Mon Ami ~!~!
Click to expand...

I think he means to take to valve cover off first and check push rods, IF all is well there (doubt it is) then take the head off and check valves.

Walt Conner


#10

G

Goober11

Thanks that sounds like a good plan. Will check out an post back.


#11

G

Goober11

Pulled valve cover and checked push rods. Exhaust was bent. Put new push rods in and adjusted valves. The valve guide look OK to me. Started and ran fine. Thanks for all the help.

I stated that it ran fine. I got to thinking that a push rod does not bend for no reason. I think I need to look at the valve train closer. Dazed an confused right now!!!!!


#12

Boudreaux In Eunice La.

Boudreaux In Eunice La.

Goober ,,,,,,,,, bent pushrods are caused most of the time by a loose valve guide that has moved........

Here is a video that shows that issue ......... Skip to 5:36 if you want toooooo....

https://youtu.be/Pl5vNccJwQs

Let us know Mon Ami ~!~!


#13

G

Goober11

Boudreaux, Thanks for the link to the video. Great info after I got over the teeth lol. So I have pulled the left head and the guide has moved. Going to pull right also. My brother in law has a 20 V twin engine. He has a machine shop and is going through the heads for me. Things are looking up. I want to think everybody that replied to my post. This is a great form and has a lot of people that are willing to help.


#14

T

Tinkerer200

I have a tried and true fix for slipped valve guides and even includes a variation of it sent to me where the head doesn't even need removed.

Walt Conner
wconner5 at frontier dot com


#15

G

Goober11

Tinkerer200 said:
I have a tried and true fix for slipped valve guides and even includes a variation of it sent to me where the head doesn't even need removed.

Walt Conner
wconner5 at frontier dot com
Click to expand...

That sounds interesting but I have all ready pulled the heads and will put rebuilt ones on Friday. Hopefully I will not need to do this again an time soon. This is the only V-Twin I have the others are single cylinder.


#16

C

cropcircle

Goober11 said:
Pulled valve cover and checked push rods. Exhaust was bent. Put new push rods in and adjusted valves. The valve guide look OK to me. Started and ran fine. Thanks for all the help.

I stated that it ran fine. I got to thinking that a push rod does not bend for no reason. I think I need to look at the valve train closer. Dazed an confused right now!!!!!
Click to expand...

Had a similar problem on my rover mower[ australia] ,briggs and stratton 15.5hp vangaurd engine.Motor stopped and i investigated ,pulled off rocker cover and found aluminum push rod had worn through and snapped.It had been rubbing against the bushing.I did not have another so i measured its length and thickness and found a piece of steel rod from an old shopping trolley that was close enough.Cut this to length and for the hardened end pieces i silver soldered a ball bearing onto each end.Been working for some months now ,does not get a lot of use .Handy to know if you ever get stuck .Any one know why one push rod is an hollow aluminium tube with hardened inserts [ the one that broke] and the other is solid steel rod ?.Seems strange to me .


#17

T

Tinkerer200

cropcircle said:
Had a similar problem on my rover mower[ australia] ,briggs and stratton 15.5hp vangaurd engine.Motor stopped and i investigated ,pulled off rocker cover and found aluminum push rod had worn through and snapped.It had been rubbing against the bushing.I did not have another so i measured its length and thickness and found a piece of steel rod from an old shopping trolley that was close enough.Cut this to length and for the hardened end pieces i silver soldered a ball bearing onto each end.Been working for some months now ,does not get a lot of use .Handy to know if you ever get stuck .Any one know why one push rod is an hollow aluminium tube with hardened inserts [ the one that broke] and the other is solid steel rod ?.Seems strange to me .
Click to expand...

Well that was certainly ingenious. You should have been able to pick up a used steel push rod from a junked engine. B&S uses an aluminum push rod on the valve involved in compression release on OHV engines for heat expansion stabilization reasons. I always recommend reversing the aluminum push rod when adjusting valves for the reason you found. NOTE: Later models use a different push rod support system and do not wear the push rod.

Your engine is an early OHV "Vanguard" single and I think you will find the parts are the same as later Intek engines as B&S switched their designations.

Walt Conner


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