cranking amps and spark

[john swenson]

if a batteries cranking amps are not up to par ..does that effect how much spark at the plugs when trying to start ? and takes longer cranking for it to fire up . seems my 21 h.p. b and s vanguard takes longer cranking till it fires up . chokes on and fuel pump and filter are new . sometimes it fires up right as i turn the key back . runs great , no problems there . have'nt tested the battery yet , it may not be taking a charge well if battery is shot . thanks j.b.

[dirtdobber]

Hey JB. Spark is a product of the magnet on the flywheel passing by the coil. As long as your battery is stout enough to spin the engine you should have good spark.

[ARGOJIM]

John, the spark is stand alone so no battery needed. You however have changed engines and should you have a fuel solenoid and or low oil pressure switch either of those could be the issue and the fuel solenoid is 12v so could be voltage or key switch related. We usually remove those.
Commonly some vanguards boil the fuel in the carberator, is this an every start issue, cold start issue or hot start issue?
My vangaurds are usually immediate after the initial longer start from sitting long periods.

[john swenson]

thanks to both of you for the knowledge shared . i had the battery tested and it checked out fine . put it back in and the solenoid kept clicking , starter not turning over like it did when i took the battery out . jumped the battery , but still clicking . jumped across the solenoid and starter cranked . thats when i discovered the connection on the solenoid going to the starter had a loose nut . tightened it down and she fired right up. so maybe i was'nt getting enough cranking for the magnet and coil to spark enough or it was intermittent . also i agree after sitting in the cold , it will take more to get it going . johnboy va.

[racerone3]

a very common issue on Briggs starters is that they will lose good contact internally. the stud that the hot wire to the starter hooks to is nothing but a carriage bolt. over time the plastic insulator that it passes through will compress due to heat and age.. all you need to do is remove the large wire from the starter and use a 7/16 wrench to SNUG not tighten the flange nut under the wire. this will snug up the contact to all 4 brushes in the starter and get you back spinning properly.

[john swenson]

thanks race ...i will go back and snug up that undernut , which i did'nt know to do at the time . more helpfull info. i've never been much of a motor guy , too busy putting them on things !! j.b.

[john swenson]

28 deg. this morn ...pulled the choke out , a few cranks and it fired right up . thanks again j.b.