My answer:

It appears you have a B&S Vanguard series engine on your Genset.

Briggs & Stratton 9 HP Vanguard OHV Horizontal Engine, Model# 185432-0242-E1

MAX RPM's - 3600

I'm hoping you first got all the contaminated sugar & gas mixtureout of the Genset's gas tank, fuel lines (replaced the fuel filter aswell), and the engine's Carb before running it. Hopefully you DID NOTrun the engine even 1 second with that contaminated sugar gas - elsewise the damage may already have been done to the engine & the OIL!Did you change the engine OIL as well? Hope so! Did you try run it thatway with or without the air/fuel Adjustment Screws set properly? If so- we can only hope for the best here.

It's hard to say if any internal damage wasdone unless the Carb first is fully broken down, thoroughly cleanedout, and then checked forproper Float setting, then re-assembled, and then adjusting theFuel/Air Adjustment Screw(s) properly.

If all looks good with the Carb Bowl then you will next need to check the air/fuel mixture Adjustment Screw(s).

That missing plastic top off the Idle AdjustScrew head can either be replaced by something closely matching it byusing Super-glue or else 5-minute Epoxy, or else can be replaced with acrimped on slotted metal cap. If you have a Dremel Tool with a diamondcut wheel you can just cut a slot in the top of the Idle Adjust Screwhead for use with a slotted screwdriver. Hopefully you are handy!

On your B&S Vanguard engine there is probably only 1 air/fuelmixture Adjustment Screw - as from the Carb parts diagram that you canfind by following the directions further below for reference. If youhave any missing parts from the Genset sabotage then those might beordered from that B&S parts list there as well.

Usually there are 2 Air/Idle Adjustment Screws side by side, but yours looks to only have 1. (See diagram at that B&S site)

If there are 2 needle valves on your Carb then turn both of them in CW just until they are fully closed or seated.

Do not force them or you may damage them.

If you have 2 adjustment screws do the following below - otherwise just set the IDLE Adjustment Needle Valve Screw accordingly.

Open the High Speed needle valve adjustment screw 1-1/2 turns CCW, andthe Idle Speed needle valve adjustment screw 1 turn CCW. Normally youcould open both up the same 1-1/2 turns CCW without any harm. Either way is fine.

This will give you the initial adjustment starting point so the enginewill start and warm up so you can do the final adjustment.

You should make sure that the air cleaner is on before you make any adjustments to the Carb.

To make the final adjustments you will need to move the governor (throttle) speed lever to the IDLE position.

Set the Idle SPEED adjusting screw (and NOT the Idle Adjustment NeedleValve Screw) to get approx 1750 RPM - if you have a TACH all the better(you have to hold the throttle lever against the screw while doingthis).

Turn the Idle Needle Valve in CW just until the RPMs slow or the enginestarts to cut out. This is a lean mixture btw. Then turn it out CCWjust past where it will idle smoothly. It will run unevenly, but thatis OK. Now turn it back in CW so that it's just halfway between the twopoints. Then release the throttle lever.

Then do the same with the High Speed Needle Valve Adjustment Screw withthe governor (throttle) set to the FAST position. You do not have tohold the throttle while doing the high speed valve. The engine shouldrun smoothly, and also accelerate smoothly from Idle to Fast withoutany hesitation or stumbling. If not - readjust as needed to get aslightly richer mixture.

The Genset AC Output Voltage is all factory preset and pre-determinedby the engine MAX RPM, and also by the LOAD you are running on thegenerator head. Use to a good DVM to double check the output AC voltageaccording to your Operator's Manual, unless your Genset has its ownanalog AC panel meter.

Please do post me a reply as to fixing your problem here, and the resolveto it by following my recommendations above. Also please rate mytroubleshooting fix as well.

Here is the B&S site info -

You can view a breakdown IPL of this engine at this site:

www.smallenginepartswarehouse.com

Just mouse click on the Shop Online Parts Look Up icon.

Then mouse click select the 2nd Folder grouping for (100000 - 19Z999)> Then click on Folder (185400 to 185499) > Then click on(185432-0242-E1) > Then click on Carburetor from the right hand sideOptions > Then you have the Carb diagram with parts list. Use theIcons in the upper right diagram to Enlarge or Shrink the Carb drawing.

This Carb may have a Float Needle and O-Ring Seat or may have just the Float Needle with a Black Rubber Tip and NO O-Ring Seat.

If the Float Needle is all metal, then there is a flat O-ring seat inthe inlet port that the needle seats against. If the float needle isthe long needle type with the Black Rubber Tip, then there is NO O-ringseat and the Float Needle seats right against the Carb housing.

Keep me posted and I'll follow up as well.

Best regards,

Frank