# Questions regarding Honda EU6500is valve adjustment



## email4eric (Dec 23, 2018)

Hello all!

I have a Honda EU6500is generator that I bought with 30 hours on it a number of years ago.

I converted it to tri-fuel using the Motorsnorkle kit from US Carburetion and that has worked really well - first on NG, then on propane when I moved to my current rural locale. I've not ever had any problems with this generator. 

I now have about 130 hours on the generator and I never had adjusted the valves so I dove in to that project today using the Honda Shop Manual.

I pulled the spark plug (which, BTW, was immaculate), and then followed the directions in the shop manual and put the piston in TDC by gently pulling on the starter rope while looking for the mark through the window on the fan assembly. It pulled easily with the plug out. Once I found TDC, I was surprised however, to find that there was no play whatsoever in either valve tappet - they both were tight. Hmmm.....

So I loosened up the jam nuts and adjusted them per the book specs: 0.15 on the intake and 0.20 on the exhaust. Put it all back together and the unit ran fine....but it also had run fine prior to the adjustment....Hmmmm....

To test whether or not I had the valves correct, I wanted to see how easily it would start using the rope pull (which I'd never before done) and It wouldn't pull -- I nearly flipped the genset over on its side! You couldn't rope start it if you wanted to. It's not a pull starter malfunction -- for some reason, it's just too much compression to overcome.

So my questions revolve around the process and whether or not I'm doing this correctly, and the rope starter findings. 

Why would the valve tappets be tight at TDC? Is that within expectations for out of adjustment valves? I would expect them to be out of spec perhaps but not tight.

What's up with the inability to turn over the engine with the rope pull? I would think that there is a compression relief mechanism. It's got electric start but there would be no way for me to start it by rope should that become necessary. As I mentioned above, without the plug in, it pulls easily. 

Why can't I hear any difference in the engine before and after the valve adjustment? 

Sorry for the long-winded post. I appreciate any educated input!

Eric


----------



## Old man here (Nov 5, 2020)

email4eric said:


> Hello all!
> 
> I have a Honda EU6500is generator that I bought with 30 hours on it a number of years ago.
> 
> ...


Are you sure that you had TDC on the compression stroke? They don't call these engines 4-stroke for nothing.


----------



## Old man here (Nov 5, 2020)

email4eric said:


> Hello all!
> 
> I have a Honda EU6500is generator that I bought with 30 hours on it a number of years ago.
> 
> ...


0.15 on the intake and 0.20
Should that be 0.0015 and 0.0020?


----------



## tabora (Sep 6, 2018)

Old man here said:


> 0.15 on the intake and 0.20
> Should that be 0.0015 and 0.0020?


The valve clearance specs are in mm:
IN: 0.15mm ±0.02 mm
EX: 0.20mm ±0.02 mm

In inches, that would be:
IN: 0.0059 ±0.00079
EX: 0.0079 ±0.00079


----------



## Ground Fault (Jun 9, 2020)

Clearances:


----------



## Old man here (Nov 5, 2020)

Didn't think about the "mm". My old brain thinks in "thousands" of inches normally. I have to see a "mm" to reboot into metric.


----------



## email4eric (Dec 23, 2018)

Old man here said:


> Are you sure that you had TDC on the compression stroke? They don't call these engines 4-stroke for nothing.


Well, only to the extent that I used the shop manual's instructions to set it per the timing mark in the window...


----------



## email4eric (Dec 23, 2018)

Yes on the clearance specs. I have a new battery arriving today and will run it after checking yet again.

I'm just leery of the fact that they were tight at TDC yet ran fine both prior to and after adjustment. 

Was hoping someone with this series honda inverter genset might chime in!


----------



## tabora (Sep 6, 2018)

email4eric said:


> Was hoping someone with this series honda inverter genset might chime in!


This is not really a generator issue; rather a GX390 issue. Many of us have that same engine in other equipment, in my case a snowblower. The output shaft is different, but all the internal specs are the same. I think you should re-check the valve clearances.


----------



## email4eric (Dec 23, 2018)

tabora said:


> This is not really a generator issue; rather a GX390 issue. Many of us have that same engine in other equipment, in my case a snowblower. The output shaft is different, but all the internal specs are the same. I think you should re-check the valve clearances.


Yes, good point on the engine vs generator application. I was hoping that someone with this model generator might confirm the TDC alignment mark through the window on the housing. I could see that the piston was topped out but beside the timing mark, cannot say whether it was on compression or exhaust. I guess that's why there's the mark!

Battery now not arriving until tomorrow or Monday so my testing will have to wait a bit. 

I appreciate everyone's help!


----------



## Dutchy491 (Sep 18, 2019)

email4eric said:


> Well, only to the extent that I used the shop manual's instructions to set it per the timing mark in the window...


Yes, but the 64 thousand dollar question is, were you at the compression stroke? The engine is a 4 stroke so ONE cycle is down, up, down, up or TWO full revolutions.... One "up" is exhaust and the other "up" is compression. When you line the mark up with the rib, ensure the piston is on the compression stroke, not the exhaust stroke. With the valve cover off and the spark plug removed, watch the valves. The exhaust will be closing as the intake opens at the top of the exhaust stroke. Rotate the engine one full revolution to reach TDC on the compression stroke, turn about 1/8 more then adjust the valves. Check that you were at the correct stroke, and double check the valves again. You don't want to bend a push rod or burn a valve etc... Dutchy



https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi5rrPytbPuAhXrFVkFHV7TDIMQFjABegQIBhAC&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DnQGk7xZuP2s&usg=AOvVaw2FHSFNv3xvyEFgGvVwvjTJ


----------



## email4eric (Dec 23, 2018)

Well all oddities have been sorted out and everything in working order.

New battery came this afternoon. Checked the valve clearance again and the timing mark is indeed correct indicating TDC on the compression stroke -- those valves were inexplicably without clearance prior to adjustment so that was weird. Hopefully no ill effects from that. Started right up, ran smooth, with no hiccups or other maladies. Then I tried starting it with the rope which I'd never done prior to posting this thread and it fired right up. I have no idea why it wouldn't pull in the prior attempt.

Love the Motorsnorkel kit and never have any issues running propane or NG. Oil (in fact the whole unit) stays visibly cleaner and the spark plug remains light grey. 

Well I now feel a little silly having posted this thread but I get a little panicky when something seems amiss and I don't have the experience that many others do.

Thanks for the support!

Cheers - Eric


----------



## Old man here (Nov 5, 2020)




----------



## rodwilsonsr (Sep 13, 2021)

email4eric said:


> Well all oddities have been sorted out and everything in working order.
> 
> New battery came this afternoon. Checked the valve clearance again and the timing mark is indeed correct indicating TDC on the compression stroke -- those valves were inexplicably without clearance prior to adjustment so that was weird. Hopefully no ill effects from that. Started right up, ran smooth, with no hiccups or other maladies. Then I tried starting it with the rope which I'd never done prior to posting this thread and it fired right up. I have no idea why it wouldn't pull in the prior attempt.
> 
> ...


Hi Eric...not to hijack the thread...but...
I have an EU6500is and I just got the motorsnorkel. I have a 1000 gallon propane tank and had a line run to the shed. The propane company installed a regulator, so I'm ready for the hook up.
Can you take some pics or offer suggestions on the snorkel install? I just want to make sure I got this installed correctly. 
Did you have any choke issues? I'm assuming this is just a matter of installing the snorkel tube and the regulator setup that came with the kit?
Thanks
Rod


----------



## email4eric (Dec 23, 2018)

The motorsnorkel kit bypasses the choke in that the tube is mounted in the throat and will no longer allow for the choke to close. I just installed per the instructions. I can try to find the photos of when I did it and post them.


----------



## iowagold (Jan 22, 2020)

i would mount the demand regulator not on the gen set.
vibration can be an issue as the diaphragm is ultra sensitive.


----------

