MMO Piston Soak ?

[Vikas]

This is for Honda GXV140 engine which is approximately 137cc OHC. I put about half oz of MMO in the cylinder. Because spark plug is almost horizontal on this engine, it was not easiest to inject MMO in to the cylinder. I used a turkey baster with a small tube attached at the end to put about 1/4 oz of MMO twice in the cylinder. I do not know how much of that dribbled out. I put the spark plug loosely back on.

I am going to let it soak for a week. Wish me luck

This engine has never given me problem during the starting. Even after a season, it starts on the first pull. But it really lacks the power and bogs down very easy. I have done almost everything that can be done to it without taking it completely apart. It had every gas cleaner imaginable through the tank and through the carb throat. I should have done compression test but if MMO makes a difference, it would be obvious during the mowing. The next step is going to be Kreen soak and failing that I will be trying Restore.

Because the engine starts and runs great, I am resisting to take apart the carburetor. Besides, I do not know if I have the skill to put it back together.

- Vikas

 

[tommygunn]

Worth a shot but for the cost of all these additives you probably could've rebuilt the engine properly, which realistically I think is the only thing that will make a marked improvement.

Good luck though.

 

[Turk]

If you drain the gas, you can put the unit on it's side so the hole is pointed up with the MMO in it!

What weight oil & how old?

How's the air filter & spark plug?

Mowing blade sharp?

 

[clarklawnscape]

as said is the blade sharp? also, as a general rule you shouldnt cut more than 1/3 the length of the blade of grass height. maybe try raising the height of cut a bit.

 

[JTK]

Vikas, is the bogging down something new?

If you had a ring/sealing issue warranting a cylinder soak, I'd think you'd be burning oil and blowing smoke out the exhaust.

Joel

 

[Quest]

Have you perform compression check and compare it to that of factory spec?

Q.

 

[GMorg]

Sometimes bogging is due to oxygen starvation. Have you cleaned the air filter lately?

 

[abycat]

all you guys make some good points but i would check compression. sounds like it has all the fuel and air and spark it can handle just not enough compression.

 

[demarpaint]

Originally Posted By: tpitcher
If you drain the gas, you can put the unit on it's side so the hole is pointed up with the MMO in it!

What weight oil & how old?

How's the air filter & spark plug?

Mowing blade sharp?



+1 The piston should be at the bottom of the stroke, and filled with as much of the solution used for the piston soak as possible. Putting the machine on its side in order to do that is a good idea.

 

[Bluestream]

I doubt the piston is dirty. How old is the engine and how many hours. A carb rebuild usually brings those old Hondas back to normal

 

[abycat]

I agree getting the gas out and tipping it would be the most effective for a mmo soak. You could easilly take the head off and inspect valves and piston top and how much the cylinder has worn.

 

[Vikas]

12 year old machine; it has always done that for many many years. The spark plug is in the front, so I can not put it on the side as the cylinder would be still horizontal. The oil is 10W-30 synthetic. The blades are very sharp. I have two sets and I change them often (that is the only time I get to use my impact wrench and torque wrench and the grinder to sharpen!).

The compression "feels" fine when I pull the cord. There is "enough" resistance. I have compression gauge still un-opened from one of my annual HFT pilgrimage. Does it matter if I do cold or hot measurement?

The filters and plugs used to get changed too often. But that has never really increased the cutting power, so these days I clean them and reuse them. I have also ran it (for short time) without filter to rule out clogged air filter. Plug looks nice when I take it out.

It starts losing speed during cutting and I have to let the clutch go until it can pick up the speed again. This one is with the hydrostatic transmission and the clutch. I have jacked up the fast idle speed as much as I could by tightening screws and cable linkage.

What I suspect is that the high speed jet (power jet?) in the carb might be clogged. However, this had been to professional few times and he claimed to have cleaned it but the symptoms never went away. The mower needed a clutch few years ago and at that time he supposedly cleaned the carburetor. Since it starts and runs fine, there is not much that I could do to push him to really "fix" it.

I see my neighbors using el cheapo Sears basic lawn mowers going through like hot knife on butter but mine keeps on losing speed on the lawn which is not even thick.

For last few years, I have been contemplating re-powering with HFT engine but I have not come across a video for the same model yet. I even purchased real printed shop manual for this mower in anticipation of taking it apart but still have not gathered all the necessary guts to really go at it

- Vikas

 

[crazyoildude]

i use strait 30 in my lawn equipment

 

[Muskieteer]

I had a similar problem with bogging down and the issue was a clogged exaust port under the mower blade. The port was clogged with black sludge/gunk. Cleaned that out and it ran just like new.

 

[Vikas]

Originally Posted By: Muskieteer
I had a similar problem with bogging down and the issue was a clogged exaust port under the mower blade. The port was clogged with black sludge/gunk. Cleaned that out and it ran just like new.


That is certainly a possibility! I have already lost the muffler shield and one of the bolt. The muffler itself keeps on hanging low as one bolt is not enough to tighten it.

 

[SOHCman]

Well that could be your problem right there, you probably have an exhaust leak due to the missing bolt. The carb is tuned for a specific backpressure, you would definitely lose power with the mixture being off.

 

[clarklawnscape]

as a side thought, you could have what ill call a rocker arm cracked, not allowing for full function of a valve, if this is the case, its only like a $4 part.

 

[Turk]

Yea, one of those 2 could be it for sure.

Let us know what you find & the results.

 

[TFB1]

I'd say it's almost a sure bet you have a lean fuel condition, or maybe restricted exhaust... It would have to have a severe compression loss to be as lazy as you say and then it'd probably be using oil like crazy... I ran a old Briggs for years that was way down on compression but it kept on going, was lazy in taller grass, but would pick it's speed back up as soon as I gave it a little break...

 

[Vikas]

Restricted exhaust probably sounds most plausible. What is the best way to clean the muffler? I was thinking car cleaner first followed by brake cleaner. Or I would just dunk it overnight in laundry detergent first.

Mechanical problem such as broken valve etc would manifest itself as horrendous noise and/or starting problem, right??

No visible smoke but there are few oil leaks that I have been trying to find. One is the o-ring at the oil filler tube. I tried couple of hardware store o-rings but I might have to bite the bullet and order replacement o-ring from internet.

I have been suspecting lean condition for years and that is why I have dumped really strong dosage of Techron (and similar cleaners) through the gas tank. I would think the internals of that carb would be clean as whistle but I would not know until I take it apart. I would need to order new gaskets etc before going there.