Briggs Quantum hot start problems

[Snapper987]

I have a snapper lawn mower with a 675 series quantum with ready start. The engine as of late has been hard to start especially when hot. When intentionally stopping the engine to empty the bag, it would take between 8 to 20 pulls to refire the engine. Could this be a dirty carb , ready start malfunction or both. Any help would be appreciated.

Engine
Briggs and Stratton Quantum 675
Code 126T05-0678-B3
Serial 08032756

 

[EngineMan]

First make sure that the autochoke is fully open when hot (off) if its working fine then clean the carb.

 

[afoulk]

First make sure that the autochoke is fully open when hot (off) if its working fine then clean the carb.

that's my guess. either that or maybe the air filter is just plugged up. either way, something is causing it to either get to much fuel, or not enough air when you start it hot.

 

[Snapper987]

Just an update. I spoke on the phone with a small engine repair shop. Based on the symptoms I gave, the mechanic told me that I most likely have a burnt exhaust valve and would cost about 80 dollars to fix. I find this hard to swallow as the mower is not quite 5 years old and has around 100 hours on the engine. Is this a common problem for a flat head and if so what would cause it.

Flat head Briggs Quantum 675
Model 126T05
Code 0678-B3

 

[EngineMan]

You could do a compression test to see how low it is, if low then do a valve check.

 

[pugaltitude]

I dont think a valve is your problem.

There is various things you can do.
Make sure fuel is fresh and clean.
Make sure spark plug is clean and set to 0.030
Make sure fuel cap is venting.
Make sure air filter is clean and clear.
Give carb a clean ie main jet and air passages.
Check intake manifold and seals for damage.

It could be that it needs a carb as the carb fitted on yours does not have an idle circuit and there is a carb available that does but try the list above 1st

 

[Snapper987]

Thanks for the comments

I plan on dropping the mower off at the shop tomorrow. I will ask about the carb. The mower has been quite good even though its not a true snapper as its an se series which more like an mtd with the snapper name. The shop charges 20 dollars for a diagnostic so hopefully they can sort it out.

As a side note the gentlemen I talked to recommended an ohv engine for my next mower. While they have advantages the flat head briggs as been around for a while so I don't see why he wasn't to keen on them.

 

[pugaltitude]

The info iv given you is from a Briggs service bulletin but its my experience from fitting the carb.
There is also adjustment on the ready start thermostat.

OHV do run cooler and better on the enviroment but the SV quantum is still one of the best engines on the market.

 

[Snapper987]

I received the mower back from the shop some time ago. Turns out that the mower had water in the fuel. Well the mower ran fine when I got my back yard. I stopped the mower for a while while I did some trimming with a weed eater. Upon returning the mower would not start when I went to cut my front yard. The engine is equipped with electric start and will crank barely when engaged. I then felt the starter motor and it is very hot to the touch. I then tried the recoil and it had more resistance than normal.

Is this a sign that the bearings have seized or is the starter gear jammed causing it to put resistance on the flywheel.

P.S. engine oil level was checked and was of proper level for operation. mower was run for approx. 30 minutes before being shut down.

Engine model number is in earlier postings