Vanguard 12.5HP/14HP/16HP/18HP carburetor cleaning

[MattA]

Those things do a great job of cleaning . Hope this is the end of it and you can get on with things.

I hope so too. I did some 10PM engine reassembly several nights this week. I left the engine disconnected from the hydraulic pump, slid forward on the frame and clamped in place for tuning. Engine starts right up. Seems to run ok. I can't load test it because its pouring rain outside.

Tuning procedure from service manual:
Turn idle screw clockwise until it seats and back it off 1.25 turns counter clockwise (Vanguard website says 1.5 turns).
Run the engine for 5 minutes prior to adjusting (doesn't say what RPM, Briggs website says half throttle).
Hold the throttle lever against the stop and adjust for 1400RPMs.
Turn the idle mixture screw clockwise until the engine just starts to slow.
Turn the idle mixture screw counter clockwise until the engine just starts to slow.
Set the idle mixture screw to the mid point.
Hold the throttle lever against the stop and adjust for 1200RPMs (forgot to do this).
Release the throttle lever. (What I found confusing is do you hold the throttle lever for the entire adjustment procedure. I did.)
If necessary adjust the governed idle to 1750RPMs (its in the 1700-1800RPMs range).
The briggs website also seems to indicate adjusting the idle at half throttle.
https://www.vanguardpower.com/eu/en_gb/ ... retor.html


The idle mixture screw isn't very easily accessible because the carb is up against the hydraulic tank. I left the engine slid forward and clamped in place. The idle mixture screw is a splined shaft once the limiter cap is removed. Its a real PITA to turn.
Idle mixture screw bottom center

Idle stop

[MattA]

I got my tractor all back together this afternoon and took it out to mow. Starts right up but still lacks power. At times the no load RPM approached 3800. I will get that fixed. I quit after about 300' and decided to change out the plugs. I put in a new set of basic champion plugs with the gap set to 0.030". Still lacks power. 6" deep grass or the hill in my yard cause the RPMs to drop right off. I can maintain 3000RPMs or so at a pace slower than my 90 year old grandmother walks. I gave up after about 3 laps around the yard. 1 lap is about 1/8 mile. I put the spark plug testers back on the tractor. Spark looks good and consistent at idle through 3600rpms. One thing I noticed and I forgot to mention this before is sometimes it sounds like the engine hunts a little while mowing at full throttle. I looked over the briggs trouble shooting flow chart I posted with the vanguard manuals. The only real idea I have is to check the governor for binding.

[myerslawnandgarden]

Matt,

Seems to me like a governor adjustment issue, I don't recall any issues with the Vanguard governors as the Onan's have so hopefully just an adjustment.

Bob

[MattA]

I reviewed the vanguard service manual section on the governor settings again today. It didn't really give me any ideas. The governor springs are all installed in the correct holes in the correct orientation. I went out to mow for a few minutes to warm it up. Still has no power. After throttling down, the idle stay a bit high at 1900RPMS+ when it should be 1750RPMs. I made a minor adjustment to the idle tang and the throttle restrictor tang and went out to mow. I left the high end RPMs on the high side, about 3800RPMs. Still no power. I decided to try and set the governor static adjustment. I've already done this several times with no results. Somewhere I read online to do this with the throttle lever in the high rpm position. I have no idea why but I tried it and went back out to mow. With the deck running driving across my yard (not mowing) the RPMS were now lower at 3300 but something was different. Felt like it had a little more power. I made a quick adjustment to the high speed tang to set the RPMS at 3600 or so and went back out to mow again. It runs good again!!!!!!!!!!!!!!!!!!!!!!! I put about an hour and a half on it cutting down 6-8" of grass. No issues. Power output is about where I remember it being. Enough to do weekly lawn mowings but get it in thick grass 6-8" high and its down to a slow walking pace. I appreciate everyone input to help me get this fixed.

[myerslawnandgarden]

I reviewed the vanguard service manual section on the governor settings again today. It didn't really give me any ideas. The governor springs are all installed in the correct holes in the correct orientation. I went out to mow for a few minutes to warm it up. Still has no power. After throttling down, the idle stay a bit high at 1900RPMS+ when it should be 1750RPMs. I made a minor adjustment to the idle tang and the throttle restrictor tang and went out to mow. I left the high end RPMs on the high side, about 3800RPMs. Still no power. I decided to try and set the governor static adjustment. I've already done this several times with no results. Somewhere I read online to do this with the throttle lever in the high rpm position. I have no idea why but I tried it and went back out to mow. With the deck running driving across my yard (not mowing) the RPMS were now lower at 3300 but something was different. Felt like it had a little more power. I made a quick adjustment to the high speed tang to set the RPMS at 3600 or so and went back out to mow again. It runs good again!!!!!!!!!!!!!!!!!!!!!!! I put about an hour and a half on it cutting down 6-8" of grass. No issues. Power output is about where I remember it being. Enough to do weekly lawn mowings but get it in thick grass 6-8" high and its down to a slow walking pace. I appreciate everyone input to help me get this fixed.

Yes, very important to synchronize the governor to the carburetor, this should be done with the carburetor throttle plate in the full open position.

Glad to hear things are working better,

Bob

[DavidBarkey]

[JSinMO]

Great job Matt! I’ve followed your journey on this, you put a lot of work in. Glad you got it running great again!

[MattA]

Thanks guys
I wasn't able to mulch up the grass clippings from yesterday so I put my hydravac on to pick up the grass clippings. Tractor did ok... it's easily overwhelmed by a lot of grass clippings especially when driving up the small hill in my yard. I've seen other people with the same setup with the same issue.