Return to the Lawn Mowers Forum | Post a Follow-Up

Briggs and stratton vanguard 16hp

Posted by chevyman1856 Ma (My Page) on
Sat, May 31, 14 at 19:26


Been trying to get my mower going and well not going very well

here is the issue

hard starting all the time
will run for 15min then die starts back up, then dies...this is not happen all the time
sometime it will start for a 2min then dies
also when it runs it will die when pto is engauged

Mower is a simplicity lth 16hp briggs vanguard 89 vintage

briggs #303777-0122-01 8905251

all new belts
new fuel
new fuel fiter
new oil
carb taking apart cleaned
new alt, and regulator, battery new,
adjusted valves
compression test cy1 70 cy2 75 cold
new ignition
new pto switch
new main engine harness

any help would be appreciated

Thanks Erik

Follow-Up Postings:

RE: Briggs and stratton vanguard 16hp

Did you try loosening the gas cap to see if it's a tank venting problem?

RE: Briggs and stratton vanguard 16hp

yes tried that no difference, not even sure that cap has vent holes


RE: Briggs and stratton vanguard 16hp

I am not familiar with the simplicity, however, the vtwin vanguard usually starts easily. Here are a couple of ideas:

1. old fuel line becomes hard and frequently develops cracks. Air may be drawn in through the cracks and around clamps.
2. fuel pumps have a pulse hose that sources crankcase pressure pulses. If this hose has developed cracks, the pressure pulses may not reach the fuel pump.
3. Pressure pulses to operate the fuel pump may be lost if gaskets are torn or perhaps the o ring that seals the oil fill tube is torn or missing.

RE: Briggs and stratton vanguard 16hp

I have to question the compression test. My 1990 Vanguard has 160 PSI compression in each cylinder. I would recheck the valve lash real easy to get them too tight. I mark the flywheel and watch the valve rock make sure no pressure from the cam on the rocker. Some models have to 1/4 pass top dead center as suggested by others.

RE: Briggs and stratton vanguard 16hp


thanks for ideas

went ahead and replace all fuel line, and the o-ring, took a while to get it to stay running, would only run at low throttle let it run there for about 10 min then finally got to stay running at full throttle ran it for a 30 min or so, deck was off will try and see if I can mow in the am

to the compression test I was think it was very low, adjusted with piston at tdc, then 1/4 past, and both rockers were loose, tighten both to .004 no pressure on rockers


RE: Briggs and stratton vanguard 16hp

I'm guessing the carb jet(s) may be gummed/varnished up a bit and the new fuel is doing a bit of "cleaning".
You might want to try a dose of carb cleaner. it might help speed things up a bit.

RE: Briggs and stratton vanguard 16hp


update started hard again, would not stay running, after about 10min it ran, added the deck back went to mow

with mower deck on, seem like mower does not have lots of power, then about another 10m or so it dies, restart won't stay running.

when turning pto on it dies

with pto off , it runs very bad like maybe on one cylinder, but I have check spark with tester and have spark


RE: Briggs and stratton vanguard 16hp

update #2

well got some used parts, tried 2 used coils and put a used carb on, cleaned carb before I put on, well it starts right up seem to run ok at idle, at full throttle and trying to engaged the deck, at first runs very slow no power, then dies, and if I turn of pto, mower does not run good, no power slow rpm even at full thottle

did have spark testers on both cyl. and have plenty and did not go away when die, also tried with kill wire off and it still died

has new pump
new plugs
all new fuel line, sea foam in the tank
adjusted valves

maybe headgaskets??

any idea would be big help

loosing my mind here

RE: Briggs and stratton vanguard 16hp

floater in fuel tank

RE: Briggs and stratton vanguard 16hp

I would check the flywheel key.
If it sheared, the ignition timing could be affected.
The flywheel could have shifted anywhere from runs perfect to doesn't run at all or anywhere in between.
Probably not the problem, but you really need to verify that.

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Lawn Mowers Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here