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Curtis B.
Curtis B., Technician
Category: Small Engine
Satisfied Customers: 26051
Experience:  have worked on and around most engine models for 35 yrs./Polaris ATV expert
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I have 2 Honda HT3813 tractors, one Running and one Parts. I

Customer Question

I have 2 Honda HT3813 tractors, one Running and one Parts. I have been trying to make the Parts tractor go but it continually floods the carburetor, and I mean flood to the point the cyklinders fill with gas. It will start fine on full choke and run on full throttle but it smokes black and will not idle. When I try to idle it, she will just run rough, flood and stop, not to start again.I am out of my wits to find the trouble. I have swapped parts from the Running tractor- carburetor and fuel pump. They run well on the Running tractor but not on the Parts tracter. I have done evreything, new spark plugs, oïl, oïl filter, air filter, checked the timing, correcte coil to flywheel clearance, cleaned the fuel tank, clean hi-test gas. the fuel pressure is at 1.5 psi on both tractors and it delivers about 375 to 475 ml per minute. On the Parts tractor, I have installed a by-pass fuel line with a valve so I was able to ajust the pressxure to about 1 psi and fuel flow to 350 ml per minute, but
Submitted: 1 year ago.
Category: Small Engine
Expert:  Curtis B. replied 1 year ago.

Both cylinders firing on the engine? Have you ran a cylinder balance test? How is the compression? Is the exhaust open and not restricted?

Customer: replied 1 year ago.
The compression is 75 and 77 psi on no1 and no2. Yes it fires on both cylinders. Will check the restriction on exhaust. The valves have the correct clearances. The fuel filter is new. Will take another compression test.
Expert:  Curtis B. replied 1 year ago.

OK, Seems like the fule has no place to go.

Customer: replied 1 year ago.
Tried to start it this morning. Could not read the oïl level. Started,It ran about 10 seconds and quit. Finally there was 3 litres of oïl and gas in the crankcase. Changed the oïl. Took a compression test cold before starting
no. 1 87 and 87 psi
no.2 80 and 80 psi
Had it running for a good 6 minutes,running very well on both cylinders, full throttle and partial choke held by hand, no air cleaner, it ran on vapors from the crankcase or fuel sucked in from the by-pass, the electric fuel pump was disconnected. When I let go of the choke, it quit.Took a compression test with hot engine;alternating fon no 1 to no 2
no 1; 65,80,84, 86
no 2;70, 80,84, 85 psiTo me the compression test is good, well balenced between both cylinders. → any restriction in the muffler, I dont know where it is, can put a long screwdriver in the muffler.The timing is done on the T mark on the flywheel with the triangle on the block and the T mark on the camshaft pulley and the triangle. There is also an F mark on the camshft pulley.Had I connected the fuel pump, it would have flooded the carb and quit.The oïl level is still good after this test.
The serial no of this tractor is(###) ###-####if of any use to you.
NOw going to try to run it with only the by-pass fuel line wide open
Expert:  Curtis B. replied 1 year ago.

Compression is ok. So let's see what leaving bypass hose open does.

Customer: replied 1 year ago.
Had it going and started to mow. It would stutter , smoke black and quit every 200 feet. I installed a switch to shut down the fuel pump whenever the engine would start to stutter and smoke black and the engine would come back to life. Was able to mow the whole lawn this way, but would flood anytime I was not attentive. There definitely is a carburetion issue with this engine. the Float and needle have been changed without any results.
Expert:  Curtis B. replied 1 year ago.

Have you swapped the carbs?

Customer: replied 1 year ago.
I have swapped the carbs and the fuel pumps and the batteries. Everything works well on the rRunning tractor, no flooding, no black smoke, no stutering, full power with either carb s or fuel pumps. both carbs were taken apart 2 or 3 times, cleaned with carb cleaner, they are ok. To stop the engine, I shut off the fuel pump and let the carb run out of gas, other Wise it will flood. The Parts tractor has full power to mow in 3 rd or 4th gear, until it starts to smoke black, stutter and flood.
Expert:  Curtis B. replied 1 year ago.

How hard would it be to swap exhaust?

Customer: replied 1 year ago.
THe muffler and exhaust manifold seem to be all one-piece. Will check that out.
Expert:  Curtis B. replied 1 year ago.

Ok, let me know.

Customer: replied 1 year ago.
I have not had a reply as to why the carb would do well on the Running tractor and flood on the parts tractor?
Expert:  Curtis B. replied 1 year ago.

It has to do with the vacuum in the cylinder. The fuel has no place to go.

Customer: replied 1 year ago.
Your answer makes no sense. The vacuum in a cylinder is created to pull in evaporated gas,not push it out in the carb. A new carb is 232$ in Canada. I am now fitting a Malbro carb from a 20 hp Kohler . Got it running now , choke off, full power, will not idle well, but it mows the lawn.
Expert:  Curtis B. replied 1 year ago.

My understaniding from you ,was you swapped carbs both ways and carb worked fine on the other unit!

Customer: replied 1 year ago.
I swapped both carbs both ways. The Malbro carb does not flood.
Expert:  Curtis B. replied 1 year ago.

Now that makes no sense!

Customer: replied 1 year ago.
I know it does not make sense, that is why I consulted you. Swapping carbs is the first thing I did without any results. Also working with a mechanic with 40 years repairing and selling Massey Ferguson tractors and machinery. It is beyond his wits too.
Expert:  Curtis B. replied 1 year ago.

OK, have a nice day!

Customer: replied 1 year ago.
I was using the Running tractor yesterday when I saw gas leaking to the ground at the frame level. The carb on these tractors have an overflow pipe about one-eight inch that runs down to a small reservoir , the size of half an orange, just outside the frame underneath the brake-pedal step. Fearing the loss of all my gaz, I stopped the engine, and plugged the overflow pipe. Upon resarting the engine, the carburetor flooded immediately, just as they have been doing on the Parts tractor all along. The engine was flooded, would not start. After leaving it rest for a short while, I resorted to
removing the plug, the engine restarted right away , did not flood, and no gaz coming out the overflow. I took off the small reservoir on the Parts tractor and it was full of dirt, plugging the overflow that was causing my problem all along.My very first question was WHY the flooding occured on one tractor and not the other even after swapping carbs both ways. I resorted to experts like you thinking you had seen this phenonmenon in other cases. It is obvious from your answers that you never worked on a Honda ht3813 and you did not consult an expert who did. I cannot rate your answers, none were helpful. I want my money back.