Briggs and Stratton 675

Charles in Aus. · Sep 16, 2014

A little off topic but this is a US engine so I will ask the experts

I have a lawn mower that has the Briggs 675 '' Ready start'' motor it's fine when it runs but does it take some effort to start !
New plug , air filter , clean fuel and clean carburettor . Good spark ,compression and fuel flow .
It seems to be over choking , plug is always wet when I pull it out .Only way I can start it is to take off the air filter , prop open the choke plate with a screw driver and give it a squirt of ether .
Starts at the second pull then and after replacing the filter runs very well with lots of throttle control and power .
I can start it again easily when hot , but let it cool down and it's the same rigmarole to get it going again .
Any ideas on this one ?

ShadetreeRet · Sep 16, 2014

Charles, you may want to go down to the garden tractor forum and post this also. There are several experts on small engines there.

Charles in Aus. · Sep 16, 2014

Thanks , Will do .

Steve@Advance · Sep 17, 2014

There is a diaphragm between the carb and gas tank. Try replacing it, and follow the instructions exactly. The choke has to be held open as the screws are tightened.

But... No guarantee that will fix it, they were a troublesome design.

Charles in Aus. · Sep 17, 2014

Thanks a lot Steve , it is a difficult engine but runs very well once started . My first self propelled lawn mower , not so common here in Aus but becoming more so . I really couldn't see myself going back to the old push variety again .

notjustair · Sep 17, 2014

I used to have a Jacobsen push mower around here that did
the same thing. It was probably from the early 70's - back
when Briggs had the throttle control as a Bakelite knob on the
fan shroud and the starter rope pulled straight up. I loved that
thing. It always ran like a top, but if you didn't pull the rope fast
enough when you first started it you had to do the same thing -
remove the air filter and put a screwdriver in to hold open the
butterfly. Never knew why it did that, but you had to grab that
rope and pull fast or it was a no-go. The starter made a snap
sound when it got to the end of the rope. Those old engines
were kind of fun.

Charles in Aus. · Sep 17, 2014

Thanks everyone , problem sorted . The 675 has an automatic choke controlled by a air driven flap and a bimetallic heat activated spring . Turns out that the spring's arm had flipped over to the wrong side of the air driven flap . Long story short , cover off two minutes to adjust and all is well .

Briggs and Stratton 675

Charles in Aus.

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ShadetreeRet

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Charles in Aus.

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Steve@Advance

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Charles in Aus.

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notjustair

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Charles in Aus.

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