Briggs & Stratton 5hp

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NM
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Briggs & Stratton 5hp

Hi, this might be a bit modern but all advice much appreciated.

I have a 21” yard king which I was given about three years ago and has been very reliable although it is showing its age, having been repaired by the original owner a few times. Recently it has been a proper s*d to start and as I now have a useable Marquis I thought I’d have a look at this one.

Soon come unstuck though. Before I get carried away does anyone know if the recoil unit comes away with the housing blower or do I have to drill out the rivets first.

Thanks Nick

wristpin
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Recoil comes off with the

Recoil comes off with the blower housing - leave the rivets alone.

It will almost certainly have Magnetron electronic ignition ( no points and condenser ) so hopefully the spark is ok but if absent have a look at the kill switch on the throttle plate before pulling it apart. If it’s been sitting around with fuel in the system I’d start with the carburettor.

hortimech
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It will definitely have

It will definitely have electronic ignition, it was made in 1994, some 12 years after the magnetron became standard. I also think he has started with the carb, it has been removed ;-)

 

NM
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Hi, thankyou for the help. 

Hi, thankyou for the help. 

Found the head gasket has gone on closer inspection which I couldn’t see because it is at the lower left hand side.

I think the rings might be in a bit of trouble as there is a bit of oil being left at the top of bore and marking on one section. Does this engine have a coating on the liner because it looks like it’s got zinc paint on the bore.

Might be worth doing head gasket, valves and decoke. Is there anything awkward or technical to be aware of removing valves. I.E. will I need an air compressor to remove valves hortimech. 

Thanks Nick

 

 

wristpin
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It looks as though that

It looks as though that engine has been burning quite a lot of oil. The bore does not have a liner, the piston runs directly in the alloy block and I suspect that your “ zinc plating” is in fact the bore material picking up or spalling. In short, it gives the impression of being beyond economic repair.  If the damage is not too deep the bore may be able to be honed oversize but in this day of cheap replacement engines it is not usually worth it. From your first image I think that there may be  signs of tin worm / deck rot so the machine is possibly a lost cause.

Are you able to post an image of the bore damage?

NM
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Morning Wristpin. Thanks for

Morning Wristpin. Thanks for your help.

Here are piccies of the cylinder bore, a bit scored. I’ve tried to take a photo all the way round the cylinder, hope they’re o.k.

The lighting could have been better.

  

 

 

Chris G
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Bet you had fun cleaning that

Bet you had fun cleaning that up..

Can you feel the scoring? certainly looks like pickup, its a bit hard to see, if I blow the pics up it goes out of focus

wristpin
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Looks as though it has  a

Looks as though it has  a fair amount of scoring for quite a large proportion of the circumference of the bore. Any proper repair would involve honing the cylinder to the appropriate oversize and fitting an oversize piston and rings - not an economic proposition for a common engine.  

If the ignition, carb and starter are OK, I would box it back together and see how it runs. May smoke a bit but still do your job or may smoke a lot ........... !

NM
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Thanks Wristpin, as you say

Thanks Wristpin, as you say an uneconomic repair on a ‘bit of a nail’ so for the sake of a head gasket and clean up I’ll see how it goes. Don’t think I want to strip this down, looks a bit complicated, especially compared to the Sloper.

Chris, only took a few goes to get head and block clean. Thinners, wooden scraper and toothbrush, mind you I had a strange taste after cleaning teeth. Maybe the amount of oil helped to prevent it sticking too much.