Briggs Engine

[Jeff P51]

Hi, can anyone tell me how a 6.5 hp engine can use the same block as a 7.25hp engine.. different head, different crank, different piston, same block. 7 25 is 190cc displacement, not sure about the other.

 

[sgkent]

just raise the working RPM and that will raise HP. HP is a function of torque x RPM. A higher compression ratio will also raise engine efficiency and create more HP. Of course the trade off is more stress and a shorter life span for the engine.

 

[Jeff P51]

7.25hp block has bad magneto side bushing..I have a good block (same part number but from 6.5 hp engine. So I should be able to transfer all the guts from the 7.25 into the 6.5 block..would there be a problem using 6.5 head with 7 25 piston and valves? I'm guessing not, but I dont really know

 

[sgkent]

I can't answer that. You will have to pull up the fiche on each engine and compare part for part.

The crankshaft and rod control the stroke. That interacts with the head as to clearance and compression. I would not mix and match the crank and head as they were designed together. You may have a piston smack the other head.

 

[bertsmobile1]

Usually with mower engines you will find some sort of restrictor plate between the carb & the engine
In the olden days the bigger engine would usually have a bigger main jet or a bigger bore carburettor .
Hp is just a number they use to sell engines
IT is the torque that does all the work
You might need to swap over your old carburettor .
While from the factory restrictor plates are fitted , usually they are not supplied as spare parts so all of the spares will be for the highest Hp engine in that displacement to reduce the spare parts inventory.

 

[Jeff P51]

I can't answer that. You will have to pull up the fiche on each engine and compare part for part.

The crankshaft and rod control the stroke. That interacts with the head as to clearance and compression. I would not mix and match the crank and head as they were designed together. You may have a piston smack the other head.

Ok, thank you

 

[ILENGINE]

Something else to keep in mind, do the engines actually say hp and not just 6.75 or 725 or 675 or something like that. Briggs went to torque ratings several years ago after a few companies were cause inflating their hp numbers, Briggs included.. After the big lawsuit. The companies were required to have something different on the engine to claim different power ratings Could be different carb, different carb jet, different camshaft, different governor spring. different ignition timing. Something that made the engine different. Good example is the Kohler Command 18-20-22 hp engines. They all used the same block. The 18 hp engine used a screw in the carb that prevented the throttle from opening over half way. That screw was missing on the 20 hp engines. The different between the 20 and 22 was the 22 used spark advance ignition.

Also keep in mind to reduce the number of replacement parts, a replacement part could be the case of a 6.75 camshaft could be replaced with the 7.25 camshaft, as a replacement repair part.

 

[Jeff P51]

Usually with mower engines you will find some sort of restrictor plate between the carb & the engine
In the olden days the bigger engine would usually have a bigger main jet or a bigger bore carburettor .
Hp is just a number they use to sell engines
IT is the torque that does all the work
You might need to swap over your old carburettor .
While from the factory restrictor plates are fitted , usually they are not supplied as spare parts so all of the spares will be for the highest Hp engine in that displacement to reduce the spare parts inventory.

Ok sir, thank you for the info

Something else to keep in mind, do the engines actually say hp and not just 6.75 or 725 or 675 or something like that. Briggs went to torque ratings several years ago after a few companies were cause inflating their hp numbers, Briggs included.. After the big lawsuit. The companies were required to have something different on the engine to claim different power ratings Could be different carb, different carb jet, different camshaft, different governor spring. different ignition timing. Something that made the engine different. Good example is the Kohler Command 18-20-22 hp engines. They all used the same block. The 18 hp engine used a screw in the carb that prevented the throttle from opening over half way. That screw was missing on the 20 hp engines. The different between the 20 and 22 was the 22 used spark advance ignition.

Also keep in mind to reduce the number of replacement parts, a replacement part could be the case of a 6.75 camshaft could be replaced with the 7.25 camshaft, as a replacement repair part.

Both engines actually say hp...the 6.5hp engine is a 2004 and the 7.25 hp is a 2013