The Forestry Forum

General Forestry => Sawmills and Milling => Topic started by: sawmiller7753 on November 27, 2012, 07:57:29 PM

Title: Need Help with 18hp B&S
Post by: sawmiller7753 on November 27, 2012, 07:57:29 PM
Hey guys need help with motor issues.  The only way I can keep the power up on the motor is to top off the gas.  When she has about half a tank she boggs down and surges.  Doesn't make sence to me.    Already changed plugs.  Oil  was changed before I left home.  Air filter is clean.  Any ideas?
Title: Re: Need Help with 18hp B&S
Post by: POSTON WIDEHEAD on November 27, 2012, 08:02:16 PM
Wow....never heard of this.  say_what
Title: Re: Need Help with 18hp B&S
Post by: Bill Gaiche on November 27, 2012, 08:02:31 PM
Check for a plugged fuel filter, collapsed fuel line or fuel pump not pumping. bg
Title: Re: Need Help with 18hp B&S
Post by: sawmiller7753 on November 27, 2012, 08:06:51 PM
Where is the fuel filter located?  In the tank?  I have a lucas mill.  Thanks
Title: Re: Need Help with 18hp B&S
Post by: beenthere on November 27, 2012, 08:08:23 PM
Carb problem maybe?

Where is tank located with reference to the carb?
Title: Re: Need Help with 18hp B&S
Post by: sawmiller7753 on November 27, 2012, 08:13:23 PM
Tank sets on top of carb.  The engine runs great when full of fuel.  Like I said when the tank is about half full it boggs down and surges and sometimes just shuts off.  Does the cap have a vent on this model?
Title: Re: Need Help with 18hp B&S
Post by: Bill Gaiche on November 27, 2012, 08:19:44 PM
Not sure on yours. Mine is in the line. Fuel pump is made of black plastic, about 2.5" round and 1" thick mounted on the engine. Trace the fuel line from the carb. back to the pump. Also check that the needle seat area of the carb. is not plugged. bg
Title: Re: Need Help with 18hp B&S
Post by: pineywoods on November 27, 2012, 08:20:49 PM
Run it till it acts up, then pull off the fuel cap. Replace cap without re-fueling. If it runs OK, you have a vent problem.
Title: Re: Need Help with 18hp B&S
Post by: 5quarter on November 27, 2012, 08:21:41 PM
I have the same engine, but probably a little older. check the lines for a vacuum leak. cap should be vented, yes. I had a similar problem, turns out the fuel pump was bad. do you have an integrated or external pump?
Title: Re: Need Help with 18hp B&S
Post by: Bill Gaiche on November 27, 2012, 08:23:36 PM
All tanks that I have seen have a vent of some kind. bg
Title: Re: Need Help with 18hp B&S
Post by: sawmillhand on November 27, 2012, 08:27:05 PM
is it a v twin  some pictures might would help. i know sometimes the float in the carb will stick. prob when you fill it up it has enough hydro static pressure to push it open.
Title: Re: Need Help with 18hp B&S
Post by: sawmiller7753 on November 27, 2012, 08:28:54 PM
Ok will pull tank tomorrow and check lines.  The Lucas Mill is about 5 years old and 50 hours.  Thanks.  V twin motor
Title: Re: Need Help with 18hp B&S
Post by: shelbycharger400 on November 27, 2012, 08:43:34 PM
my kohler 17 hp did that, pulled the carb and pop'd the float out, It had gas inside of it.  cheapy plastic float. 
Title: Re: Need Help with 18hp B&S
Post by: Hollis Alaska on November 27, 2012, 10:42:22 PM
Just had this happen with the 18hp on my wood-miser. Repaired it by just rebuilding the carb, the problem was the fuel pump diaphragm. You can get just the fuel pump diaphragm or carb kit with them included. Not much to putting the kit in and that way you can clean the bowl and check things out.

Gary
Title: Re: Need Help with 18hp B&S
Post by: Chuck White on November 28, 2012, 05:40:37 AM
I think pineywoods has it pegged, it sounds like a vent problem.

Title: Re: Need Help with 18hp B&S
Post by: Al_Smith on November 28, 2012, 05:51:21 AM
Just as general info more times than not on a Briggs pulsa-jet carb problems usually are related to the diaphragm fuel pump .

In addition to that with a little age gunk,sludge etc blocks the main jet from settlements in the bottom of the float bowl and you have to run them about half choked or they lean out and die .

Okay something like a mower engine or maybe this mill engine might sit for a while .Then they want to take a fit on you .Clean the carb up ,maybe replace the fuel pump diaphragms which don't cost much .Blow all the jets out with compressed air .That usually fixes them for a while but the problem comes back given enough time .

Something like a mill engine is running with a bunch of dust swirling around .Just like a chainsaw engine in spite of filters little tiny bits of stuff find their way into the carbs .

Funny though on a mower engine that gets ran more frequently during grass cutting time they don't cause as much grief .It's when they've sat for a spell the problems arise .
Title: Re: Need Help with 18hp B&S
Post by: larson1951 on November 28, 2012, 06:01:52 AM
try it with the cap off or very loose
if that doesn't work you probably have a bad float or your main jet nut (plug on the bottom of float bowl) might be dirty or have water
if you don't have a float bowl you may have bad or torn diaphram
Title: Re: Need Help with 18hp B&S
Post by: thecfarm on November 28, 2012, 06:47:12 AM
Hollis Alaska,welcome to the forum. I checked out your website. Looks like quite the place.
Title: Re: Need Help with 18hp B&S
Post by: Solomon on November 28, 2012, 06:49:40 AM
Quote from: shelbycharger400 on November 27, 2012, 08:43:34 PM
my kohler 17 hp did that, pulled the carb and pop'd the float out, It had gas inside of it.  cheapy plastic float.
Thats a good idea,  do you know anyone who would want to mess with you or pull a prank on you.  Sounds like a coated ping pong ball in your tank.  is the fuel cap opening large enough the someone could have inserted something like that , that floats and blocks the fuel line when the fuel level gets lower?????????? smiley_devil
Title: Re: Need Help with 18hp B&S
Post by: John Bartley on November 28, 2012, 06:54:54 AM
Already mentioned .... this is a +1 for a dirty fuel filter or a plugged tank vent.

John
Title: Re: Need Help with 18hp B&S
Post by: Al_Smith on November 28, 2012, 07:18:11 AM
Ping pong ball in the gas tank. Never heard that one .Now chewing gum under the metal cap vents on old small engines used to be a thing or a potato jammed  in a tailpipe with a broom stick .

There's all kinds of nasty tricks but I won't go into them .
Title: Re: Need Help with 18hp B&S
Post by: ArtoisDave on November 30, 2012, 02:01:29 AM
On the Briggs, check to see 2 items.
1) If alcohol is used in your fuel, check to see if moisture has caused a clear blob in the bottom of your fuel tank. Clean the tank and filter.

2) An air bubble in the fuel filter. Purge the line and fiter.
Title: Re: Need Help with 18hp B&S
Post by: Sixacresand on November 30, 2012, 08:50:45 AM
I have a 18 horse 2 cylinder BS on a mower which is still running after 25 years.  If the fuel filter is bad, it would have enough gravity pressure with a full tank to push gas through the filter but not enough when the tank is half full.  If fuel is getting through the lines, then it is probably the pump diaphram.  If the problem is the tank cap vent, it should run fine after loosening it.  Good luck with it.
Title: Re: Need Help with 18hp B&S
Post by: sawmiller7753 on December 02, 2012, 09:59:55 AM
Ok guys I am back home from my trip to Ohio.  Sawed up around 800 bft. of burr oak and red oak.  Left dad to stack it.  Some really nice boards.  The tree was damaged during a big storm this past summer.  Well what we found is and I believe is causing the issues is, white junk in the filter and tank.  It is almost like teflon pipe dope.  Called around to see if we could get a filter with no luck, so we cleaned best we could and cleaned tank.  Ran really good lots of power but started acting up right at the end of sawing.. We finished sawing but looks like I may have to do a royal cleaning now that I have some down time.  Any ideas of what the white junk is?  Could it be the filter itself?  Thanks for all the help.  I was worried about now getting all the wood milled, but we did.  Thanks guys.
Title: Re: Need Help with 18hp B&S
Post by: dgdrls on December 02, 2012, 11:37:05 AM
where is your fuel coming from and being stored in?

I wonder if your experiencing degradation of the fuel lines/tank from the ethanol fuel?


DGDrls
Title: Re: Need Help with 18hp B&S
Post by: Al_Smith on December 02, 2012, 11:58:27 AM
I assume it just has a standard in line fuel filter and if that's the case those can be purchased at about any discount parts store like Autozone ,Parts America etc .You'll about have to tell them exactly what you need it for because if you say a  B and S engine most counter people will give you the deer in the headlights look .

That gunk in the fuel tank could have came from anywhere .Maybe the can you used to dump fuel in for the engine even .If it's in the carb though it could be a reaction between the ethanol laced gasoline and the aluminum of the carb .

Quite frankly I think what you have is typical of a small engine or any engine for that matter which has sat unused for a period of time .My only suggestion is perhaps topping the tank off with gasoline containing  some type of long term stabilizing compound .Of course I may evangilise about it but be fighting the same thing next spring when I get the mower out .I'm not very good at following my own advice or so it seems .