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Discussion Starter · #1 ·
Hi

I was referred here by a guy on garage journal about my honda g41 not starting, I'm from australia and can't find any information locally or on the net. The local mower guy told me it can't be fixed and just to buy a new motor over the phone.

I recently purchased this 1970s (maybe earlier) Reel Mower.



It was sold to me as a 'runner', however the spring in pullstart had snapped, so that was not on the motor at the time.

It Runs a Honda G41 (171cc OHC) which is possibly a replaced motor, i cant find much info on the mowers and what motors they came with.


I repaired the pullstart, and tried to start it with no luck. I removed the carby and took to it with the carby cleaner spray.








I removed the Main jet and tube, and i sprayed carby cleaner in every hole and made sure it came out the opposite openings.

While the carby was off, i checked the intake valve wasnt jammed. Which it wasnt. I also checked the exhaust valve, which is also not jammed.

I sprayed a bunch of starter fluid into the carby, and it almost ran, (2 puffs) then died.

So things i have done:
- Fresh Fuel (only 91 octane not 95 or 98 and no Lead replacement)
- Confirmed spark
- replaced plug from champion, to correct NGK with 0.020 gap
- Confirmed intake and exhaust valve not jammed)
- Confirmed no blockage in muffler
- Minor Carby Clean
- Cleaned Sediment Filter, Stop **** on Fuel Tank, cleaned Fuel line
- Confirmed Points are moving, not sure on timing
- Tried Combinations of Choke, throttle, starter fluid.
- On the intake stroke I can hear the carby fizz and see the needle get wet then dry when i turn the motor over by hand.
-Compression Tested motor, 100PSI with wide open throttle
- Confirmed flywheel key is not sheered.
- tried to get it to kick over with my drill as an electric start

I have no timing mark, it has rubbed off the flywheel.

More pics







Cleaned out all this junk




EXH open

INT open

Combustion stroke


VIDEOS:
Trying to start sorry a bit shakey



The temperature is 31c / 88f here currently.

Where do i go from here?

So my possible list?
  • Timing wrong
  • Weak spark issues
  • Leaking valves (have good compression though?)
  • Other Issues?

Thanks in advance, Sorry about all the pictures, its compiled from a whole thread on another forum. Im pretty clueless about ignition, points, timing etc.

Cheers
Ken:confused::confused:
 

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Cool mower! What brand is that? Lots of folks here really like to hear more about the mower too, but let's see if we can't get the engine running first.

You've done a lot, and that little Honda has rewarded you with trying to start, which is a good thing, and means you're on the right track.

Just to make sure the fuel is in fact getting to the carb from the tank, does the fuel run out of the fuel line when you disconnect it from the carb and open the petcock? If not, then there may be a blockage in the tank preventing fuel to get to the filter and fuel line you cleaned.

Then, I'd go over that carb again. There are little passages in those things that are finicky at times if they aren't clean as a whistle.

I've been searching for information specific to the carb to see if I can find something more useful to tell you. Haven't found anything yet, but I'll ask my favorite dealer if he can shed some light on it. In the mean time, I did run across this Honda manual and if you scroll down far enough you'll find the G41 specs.

http://vrr.dyndns.biz/Docs/OLE/HondaService/EngineServiceSpecChartsW-OTR51141G.pdf

Here's what is says specifically under the engine section of that manual for the G41.

Engine oil capacity: .85qt.
Transmission oil capacity: G41CD: 400 cc (13.5 fl. oz.) G41RD: 300 cc (10.1fl. oz.)
Standard spark plug: NGK B4H
Spark plug gap: 0.7mm(0.028in.)
Float hight: 2.0 mm (0.8 in.)
Engine speed: Idle: 1,400 ± 100 rpm Maximum: 3,900 ± 100 rpm
Compression: 588 kPa (85 psi)
Valve clearance: IN and EX: 0.07 mm

The only other place that engine number shows up in that manual, and in all the searches I've done so far, is on an E1500 generator.
 

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Discussion Starter · #3 ·
Its a scott bonnar supercut 20"

I know the carb may not be perfect but even using starter fluid or a cap full of gas straight into the cylinder it wont even kick. Obviously this bypasses the carb.

I appreciate the info. Basically i would like to get it running before i restore the mower.

Id really like to keep the old honda on there rather than replace it.
 

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I thought it sounded like it was running on something in that third video of yours. What sort of adjustment does it look like there might be to the timing?

It might pay you to get a shop manual for the engine for reference now and in the future.

Honda Factory Service Manual 1972 G41 General Purpose Engine

Honda General Purpose Engine G41 Shop Manual | eBay

Hang on though, maybe one of our other gurus will have some suggestions for you too, and I'm waiting to hear from my favorite Honda dealer to see if he has any pointers.
 

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Here is what my favorite Honda dealer had to say.

Those older side valve engines with points and condenser did have timing marks and you set the point gap not by the gap , but by setting the points to open at the point of the timing marks on the flywheel and engine block were in alinement. There was a tool to accomplish this while the flywheel was removed. I believe I have that tool , and will sell it for a million dollars , or a yellow Lamborghini Hurricane with beige interior, leather , of course! :))
He (or she) should inspect the coil closely for any signs of cracks/splits in the black plastic covering of the coils body. If any cracks are present , that's a problem.
IF his spark is "OK" , motor should at least pop some if he turned off the fuel completely, and just shot a small amount of lighter fluid or similar in the air intake snout ( I would think) His spark plug should be in tip top condition. I have seen instances where spark appeared O.K. , but under compression it wasn't.
 

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I thought it sounded like it was running on something in that third video of yours. What sort of adjustment does it look like there might be to the timing?

It might pay you to get a shop manual for the engine for reference now and in the future.

Honda Factory Service Manual 1972 G41 General Purpose Engine

Honda General Purpose Engine G41 Shop Manual | eBay

Hang on though, maybe one of our other gurus will have some suggestions for you too, and I'm waiting to hear from my favorite Honda dealer to see if he has any pointers.
Nope thats running off my milwaukee 18v brushless drill with a socket on the flywheel.
The timing adjustment i have is just moving the points bit left and right about 1/4 of an inch?

As much as id like a manual, the price of them posted would be as much as i paid for the mower. Most of the info i need i have found on the net, through pictures of the manual.

Here is what my favorite Honda dealer had to say.

Those older side valve engines with points and condenser did have timing marks and you set the point gap not by the gap , but by setting the points to open at the point of the timing marks on the flywheel and engine block were in alinement. There was a tool to accomplish this while the flywheel was removed. I believe I have that tool , and will sell it for a million dollars , or a yellow Lamborghini Hurricane with beige interior, leather , of course! :))
He (or she) should inspect the coil closely for any signs of cracks/splits in the black plastic covering of the coils body. If any cracks are present , that's a problem.
IF his spark is "OK" , motor should at least pop some if he turned off the fuel completely, and just shot a small amount of lighter fluid or similar in the air intake snout ( I would think) His spark plug should be in tip top condition. I have seen instances where spark appeared O.K. , but under compression it wasn't.
Thanks for that, sounds like this guy knows his hondas! The timing mark was a yellow painted fin on the flywheel, this has been rubbed off after years of work. I will find TDC and work back from there to 22*btdc.
Ill inspect the coil, it could definitely be toast!
The spark plug is brand new.

Might of been just a poor ground but the spark did look on the weak side.
Awesome! Thanks for watching the video, i thought the spark was weak too, but someone said if its blue, its enough, Its not a v12 jag.
 

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I've bought my share of Honda manuals over the years, and I may just have more money in them than the equipment I bought them for, but the information in them is sometimes worth their weight in gold.

I just wonder if it would be possible to replace your points and condenser with one of these. A Nova II electronic ignition module.

Robot Check

I've used them on a few different vintage engines, and others have too, with great success. They are inexpensive and easy to install.
 

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Discussion Starter · #9 ·
What ive seen from the scans of this manual, its quite vague. Nothing like a haynes service manual.

Someone on the other forum suggested a b+s magnetron ignition setup. It might be a good option for once i work out the issue i have. I dont wanna mess with it too much until i know its a good runner

I messed with the timing a bit tonight and still no luck. I want to get the thing up on a bench to pull down. Lying on the ground is no good.
 

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My guess is also, weak spark...Hard to tell outside, spark under compression [especially the 100#you measured can be a "No spark in cylinder" and says eng does Not have a comp release mechanism]...I'd do a quick file of the points and re-try with a fuel prime.....and keep the capacitor in mind too...You an do a crude check with a VOM to verify if capacitor is good...should the points prove to Not be the problem..
 

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Hi there I ended up with your G41 and it's runner now, I replaced coil and condenser, parts for this model were not available so I retro fitted with parts from a different model Honda.
 
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