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Honda FR500 Tiller fuel in oil

#1

Aubs

Aubs

Does anyone have a shop manual for this machine? I am going to be servicing it next week for fuel in oil and I suspect (hope) that the float may be set wrong or leaking (sinking) letting fuel wash the cylinders during operation.
I looked all over but found no service specs like float height and such.
Runs good, has fuel shut off that functions correctly.
I will be checking the compression when I get started, but like i said it starts runs good and does not smoke.
Thanks!


#2

M

mechanic mark

Post all Honda Engine #'s from engine, thanks, Mark


#3

B

bertsmobile1

Honda sell their manuals , including the service manuals on ebay
You will need to buy 2
One for the engine
and
one for the tiller.
The manuals are written for techs in a workshop with all of the Honda factory tools , not novices so are of limited use.
The usual reason for fuel in the oil is dirt under the float valve preventing it from seating properly
If this is a real tiller then the instructions for cleaning the carb are to be found on out door power info repairs page, however that has lots of photos but no numbers.
To check the float height tip the carb upside down
The float should sit level with the bade of the carb body .
To check if it is working you tip it upside down & try to blow through the fuel inlet
If you have a pressure pump it should hold back 14 psi


#4

Aubs

Aubs

Back home from long work trip, gonna check this tiller today. The engine case has G200-2218552 stamped in it by the way.

The oil definitely smells of fuel, so I will start with checking the carb for overflow (or float sinking) and float seal, find some new oil, then a compression check if needed. I would love to find the compression specs if possible.

Time to get greasy.


#5

B

bertsmobile1

because of the decompressor the actual compression at cranking speeds will vary with the valve lash
Thus the actual compression numbers are rarely published ans we use leak down to check he rings and valves


#6

Aubs

Aubs

The Kei Hin BB carb seems in order. jets and passages clean. I left the gas on with the carb loosely mounted and no fuel leaked from carb throat. after cleaning I observed the float valve stopping the flow as soon as it reaches the valve seat (float parallel to bowl seal).
In my mind the only other way fuel could mix with oil on this tiller would be blow-by from rings??
Is it possible a leaking head gasket could result in fuel oil mix? The engine does have oil leaking from around that height.


#7

Aubs

Aubs

Tested compression (with slight head gasket leak) and it seems to be around 40psi.
I don't have a leakdown tester yet, but does this sound like the rings could be worn enough to mix fuel in oil? G200 engine.
Head gasket coming, but it is difficult to find service manual that details the disassembly needed to replace rings. I see some time-lapse videos online from other countries, but no clear how-to.
They seem to rotate to TDC and then pull camshaft.
Then rotate to BDC and remove con-rod bolts, followed by pulling crankshaft, then push piston out.

I would really like to find detailed info but the service manuals online seem overpriced or sketchy online stuff that may not be helpful.


#8

B

bertsmobile1

NO
Worn rings will cause the plug to oil up not the crankcase to fill with oil.
That can only happen due to a bad fuel pump ( where fitted ) or bad float needle
ONLY 2 causes
You have been watching way too many brain dead idiots on You Tube .


#9

Aubs

Aubs

Crankcase getting fuel in oil you mean. The cylinder is awfully carbon coated. Valve seats are not clean too. I suppose that could create some blow-by...
The fuel was not passing the float needle during testing

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#10

Aubs

Aubs

That was wrong-headed of me. Valve seals wouldn't let be involved during compression stroke since valves are shut, duh.
Decided to put head back on and do another compression test, a baseline one and a second with a bit of oil in plug hole.

However, instead of using the pull start I wrapped a long strap around flywheel and got 5 or 6 revs by pulling it, and the dry cylinder test showed factory spec 80-85 psi this time, so i reckon the rings are decent after all?


#11

Aubs

Aubs

oil seepage at the head, slow leak over time, took awhile to clean this machine.

Head gasket was pretty flat andstiff but more or less intact.

Took awhile but I got the mating surfaces and the piston, valves and chamber de-carbon-ed and clean.

Cylinder looked normal with plenty of cross-hatching visible.

85 psi compression.

Zero gas leaking from carb float valve or petcock.

I dont know what else I could check for the stated fuel-in-oil problem, so I assembled it and re-checked fuel and spark.. starts and runs fine. I tilled some earth for awhile and did not detect fuel in oil.

Sent it back to its home to see how it does the rest of the spring.

Time will tell


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