# Briggs and Stratton 3 HP engine



## Twinpaddle (Oct 19, 2014)

Hi I have a 3 HP Briggs and Stratton engine when I turn the engine over the points doesn't move IE they won't open or close ? The cam is rotating but the little pin that is under the points and rests on the cam shaft doesn't move it is solid. Any ideals


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## Basementgeek (Feb 7, 2005)

Hi and welcome to TSF

Have you tried to replace the points? They do wear out.

Make sure that you lube the cam. If the cam gets dry it will wear the parts that rides on the cam.

BG


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## Twinpaddle (Oct 19, 2014)

Hi thanks for the quick reply yes i have put new points in, and i have lubricated the points cam follower but, but as i say it is still stuck solid and will not move when the cam shaft is rotated.


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## Basementgeek (Feb 7, 2005)

Still have no idea what is wrong.

Remove the points and see if they move up and down by hand (the contacts).

Almost sounds like you did not install them right. Make sure you set the gap at the top of the points.

BG


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## wristpin (Oct 24, 2014)

Guess that the "little pin" aka Breaker Plunger, has seized and that the cam has worn the end away. 
You've got to get the old plunger out, hopefully by gripping it with pliers and levering it out. Worst case is that it wont move and you end up having to either drill it out (lots of bits of fibre inside the engine) or dismantle the engine and tap it out with a punch.
When installing the new plunger, lube it with engine oil and install with the little groove outward.
Initial seizure can be due to corrosion from moisture in the breaker point housing due to leaving machine outside or excessive pressure washing.
If the cam itself has become rusty it will wear the new plunger!


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## Basementgeek (Feb 7, 2005)

Did not a new pin come with the points ? I would think grease would be better than motor oil.

BG


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## wristpin (Oct 24, 2014)

Quote "Did not a new pin come with the points ? I would think grease would be better than motor oil." Quote

The breaker plunger is not included in the genuine BS points sets sold here in the UK , don't know about elsewhere. The BS manual makes no mention of initial lubrication of the plunger , it's just something I've always done and as it will end up running in oil it seemed logical to put a drop on it so that it doesn't run dry during the initial start up.


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## Basementgeek (Feb 7, 2005)

You are correct wristpin, it is a separate item. Hope they installed groove up.

Here, at least in the USA, B&S got rid of points set ups back about 1982

BG


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## wristpin (Oct 24, 2014)

Basementgeek said:


> You are correct wristpin, it is a separate item. Hope they installed groove up.
> 
> Here, at least in the USA, B&S got rid of points set ups back about 1982
> 
> BG


About the same time scale over here. Was working on a '79 08000 series last week and that's the first set of points I've seen in months. When I had the business we always used to save the Magnetron armatures from scrapped machines and use them for a quick and reliable update on service customer machines. Now in retirement it's back to cleaning points!


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## Hired Wrench (Nov 19, 2014)

The plunger is probably stuck. You might be able to free it, but if not, it's not incurable. The easiest fix would be a points replacement module. They sell for about $20 and replace the points and condenser with a solid state module. 

Another option would be to find a coil for a more modern version of that engine that doesn't use points. I think most newer B&S "classic" 3.5 hp engines use the coil you'd want. Where I live, I see mowers like that at the dump all the time, so if I wanted to do it for free, I'd just harvest one from there.


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