Honda BF20 2005 20 hp four stroke rough running & stalling.

Have a BF 20 that has seen little use in the last year. It now won't start initially without using starting fluid. Once it starts will idle and run at low rpm's for several minutes running very smoothly then all of a sudden runs really rough, then stalls. Trying to give it throttle does not seem to help. Restarts almost immediately (without use of fluid) and the problem repeats itself. Has new spark plugs, new fuel pump, new inline gas filter, new water separator. Also recently replaced choke cable. Water pump discharge seems to have good flow. Have flushed clean gas through carburetor & drained. Any thoughts or help would be appreciated. Could it be something electrical?

Re: Honda BF20 2005 four stroke rough running & stalling.

Fuel left sitting in the carburetor tends the plug up the tiny passage ways ( jets ) in the carburetor.---------------I would start with a careful examination / cleaning of the carburetor.-----------A spray with so called " carburetor cleaner " is not good enough!

Re: Honda BF20 2005 four stroke rough running & stalling.

Thanks. based on your suggestion, I have just bought a carburetor cleaner soaking type solution. Will let you know how it turns out.

Re: Honda BF20 2005 four stroke rough running & stalling.

You have to be careful with some of that stuff, it will disolve / damage plastic parts !!

Re: Honda BF20 2005 four stroke rough running & stalling.

Reinstalled cleaned carb today. Also completely flushed all of fuel system and filled with fresh gas. Engine still needed starter fluid to start but initially ran smoother and throttled up nicely however after about five minutes, previously reported symptoms recurred with rough running and then stalling. Engine would restart easily only to run for a time & then stall. Any further ideas or suggestions would be appreciated. Thank You.

Re: Honda BF20 2005 four stroke rough running & stalling.

Check all fuel lines for leaks ----------------------------Including the pick-up in the tank.----------------Have seen the hose in the plastic tanks " rotted away " from the stuff called gasoline today

Re: Honda BF20 2005 four stroke rough running & stalling.

A couple of questions:
Did you completely disassemble the carb and then immerse it in your cleaner or did you just drop it in and let it soak?
Does the accelerator pump (item #14 in the link below) move up and down with the throttle?
Also, is the accelerator pump plunger "cap" (item 12 in the linked parts breakdown) completely intact and not torn?

Re: Honda BF20 2005 four stroke rough running & stalling.

Had recently replaced gasket on fuel tank and inspected all interior parts which seemed ok. Will replace a suspect length of fuel hose...thanks again

Re: Honda BF20 2005 four stroke rough running & stalling.

I removed all external plastic & rubber parts including pump plunger "boot" which is intact. Accelerator pump does move up & down w/throttle. I did have a problem w/one of 4 screws on float chamber cover being frozen and gave up on it for fear of snapping it off so I never accessed the float & inner chambers. I did however remove the float chamber drain plug prior to soaking in the parts cleaner for about 1 hour. I rolled & agitated the soaking carb several times while in the cleaner to remove air. Blew out the carb & all exposed ports after cleaning with compressed air prior to re-installation w/new gaskets I had on hand. Any ideas? Thanks.

Re: Honda BF20 2005 four stroke rough running & stalling.

Carburetors ----MUST ----come apart for proper cleaning.------------There are too many small passageways in there.-------------If you do not want to do this --Buy a new carburetor !!

Re: Honda BF20 2005 four stroke rough running & stalling.

Yep, the float bowl on these is a real area of headaches when it comes to getting the carb to work reliably. Your symptoms tell me that:

A. The passages at the bottom of the bowl are still plugged. Having to enrich to start with ether (which I strongly urge you to stop doing) indicates this. Sometimes the vacuum break passage is so plugged it is easier to just replace the bowl.

B. You need to take that bowl off to in order to verify that the accelerator passage in the main body is clear. You need to find the passage, prop open the throttle plate and then spray WD-40 or carb cleaner into that passage and make sure that a stream of liquid comes out of the little brass tube at the front of the throttle bore and shoots about 3 to 4 feet out the back of the carburetor. If it doesn't, then you need to insert the plastic straw from the spray can in through the back of the carb and place it over the tiny orifice in the brass tube and "backflush" that tube and passage. Keep this up until the stream is good and strong out of that brass tube. If not, the engine will never run right.

C. The bowl needs to come off in order for you to inspect the inlet needle to see if that cleaner you used damaged the neoprene tip or the float itself as it is not made of metal either. I'm guessing that they are ok since it ran for a bit and you didn't mention the plastic lip on the throttle plate being damaged.

D. The bowl needs to come off so that you can clean and inspect the "jet set" (item 18 in the link below) as well as replace, carefully replace, the o ring (item #1) at the top of the jet set. That little tube and that little tiny o ring are most important for proper fuel delivery through that carb.

Do all that and you will have better results.

Good luck.

http://www.boats.net/parts/search/H... TO BAMJ-1299999/CARBURETOR (AUTO)/parts.html

Re: Honda BF20 2005 four stroke rough running & stalling.

^^^^^^ listen to him!!!!

Re: Honda BF20 2005 four stroke rough running & stalling.

Thanks for the detailed response. Any tips on breaking the 4th screw loose on the float bowl cover? Have tried soaking w/liquid wrench & wd40 as well as have hit head of screwdriver very firmly w/hammer several times w/no results. Was hesitant to try heat for fear of plastic or rubber parts inside. What do you think? Soaking the whole carb in the cleaner did not help either.

Re: Honda BF20 2005 four stroke rough running & stalling.

About all you can do with those screws after they're "boogered" up is to use a Dremel with a cut off wheel and make a new slot for a flat blade screwdriver. They will usually come then because the heat generated from the wheel cutting the slot expands the metal and then it shrinks a bit when it cools. If not, then use the wheel to completely remove the head and, with the bowl off, you can grab the nib of whats left of the screw with Vise-Grips or pliers. WD-40 and Liquid Wrench are not very good for anything but cleaning. Use a product called PB-Blaster for penetrating purposes. Available at most auto and hardware stores where you're going anyway to buy a new screw. Works like magic on most things but not on those screws.

One thing I didn't mention in my "detailed" response is that you should use that carb cleaner straw and spray into the hole where the "jet set", with it's oring, pushes up into the top of the carb throat. That is the main passage feed for all the circuits except enrichment. If yours is electric, the enrichment is from the carb bowl through the electric solenoid pin. If it's a manual choke, there is no enrichment circuit to worry about. I'm guessing yours is electric because of your symptoms. Is that right?

You should, once again, prop open the throttle plate so that you can observe the liquid coming from the three tiny orifices at the top of the throttle bore. The one that you can see when the throttle plate is seated or closed is idle and the the other two are the high speed and transition holes. All three should have small 1/8" to 1/4" "gushers" of liquid coming out of them when you get that little plastic tube seated and are shooting the juice to that passage. The high and intermediate are easily "backflushed" and cleared but sometimes you will need to remove the idle mix screw completely (real pain in the butt) to get it to flow properly. It too uses the little "ITEM 1" oring and that should be replaced if disturbed. If it were mine, I'd reseal the whole thing with new gaskets.

Let us know how you make out.

Re: Honda BF20 2005 four stroke rough running & stalling.

Thanks again. Good trick to know on screw removal. Although screw head is still intact will still use dremel on it. Mine is Manual, not electric. Will order full replacement gasket set, too.