Hard starting Honda push fixed with pre-mixed Sunoco 2 stroke?

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Nov 24, 2003
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Middle of Iowa
I have a Honda push mower starting its fourth year of service. For the past two+ years it has been extremely hard to start when cold. After it starts, it is easy to restart until the next mow.

Here is what I have tried:
new spark plug (old one looked perfect...heck it was hardly "old")
changed air filter (wasn't needed)
verified choke is activating when cold
1/4 can techron in a tank of fuel - did this a couple times
I always mix 1 ounce TCW3 per 5 gallons gas, and use ethanol free premium 91 octane

None of the things above have had any impact on the hard starting. Most of the time I need a slight whiff of starting fluid to get it to kick off. I just basically gave up on trying to fix it. A couple of weeks ago I was trying to beat some rain and started mowing. I thought I had some gas left in my can and got about half way through before the tank ran out. Went to grab the can...RATS, it was dry. It was 15-20 minutes away from raining, so I grabbed my gallon of pre-mixed engineered 2 stroke 40:1 fuel I use for my blower (used to use on all my 2 stroke equipment, but all I have left is a blower). It was expensive, but the only way to finish the mowing before the rain. I dumped the rest of what I had in the tank which almost filled my mower and finished mowing. The mower ran great...no concerns, no smoke.

I pulled the mower out the next weekend, and to my surprise it started FIRST PULL. It has not done that since the first year I owned it. It also seemed to have a bit more power (yes, probably my imagination). I got to mowing and refilled with normal gas when needed.

Fast forward to today, it has now started cold on the first pull three times in a row on straight gas. I don't know what is in the engineered fuel, but it seems to have solved my problem.
 
TruFuel 4 cycle may be worth exploring. Regarding Honda mowers being hard to start in general, the thermowax thingie, and Choke Control Assembly, both affect ease of starting. Both together are only about $20.
 
TruFuel 4 cycle may be worth exploring. Regarding Honda mowers being hard to start in general, the thermowax thingie, and Choke Control Assembly, both affect ease of starting. Both together are only about $20.

The auto choke was working...it closed when cold, and was wide open when warm.

Running engineered fuel long term is not an option. It would be cheaper to just buy a new mower that would run on regular gas ;-)
 
Definitely seems fuel related. Perhaps its running too lean like most new O.P.E. engines are doing these days. I like to widen my carb jets ever so slightly with a welding tip cleaner. It always results in much easier cold starts, more power and no downsides whatsoever.
 
I have a Honda push mower starting its fourth year of service. For the past two+ years it has been extremely hard to start when cold. After it starts, it is easy to restart until the next mow.

Here is what I have tried:
new spark plug (old one looked perfect...heck it was hardly "old")
changed air filter (wasn't needed)
verified choke is activating when cold
1/4 can techron in a tank of fuel - did this a couple times
I always mix 1 ounce TCW3 per 5 gallons gas, and use ethanol free premium 91 octane

None of the things above have had any impact on the hard starting. Most of the time I need a slight whiff of starting fluid to get it to kick off. I just basically gave up on trying to fix it. A couple of weeks ago I was trying to beat some rain and started mowing. I thought I had some gas left in my can and got about half way through before the tank ran out. Went to grab the can...RATS, it was dry. It was 15-20 minutes away from raining, so I grabbed my gallon of pre-mixed engineered 2 stroke 40:1 fuel I use for my blower (used to use on all my 2 stroke equipment, but all I have left is a blower). It was expensive, but the only way to finish the mowing before the rain. I dumped the rest of what I had in the tank which almost filled my mower and finished mowing. The mower ran great...no concerns, no smoke.

I pulled the mower out the next weekend, and to my surprise it started FIRST PULL. It has not done that since the first year I owned it. It also seemed to have a bit more power (yes, probably my imagination). I got to mowing and refilled with normal gas when needed.

Fast forward to today, it has now started cold on the first pull three times in a row on straight gas. I don't know what is in the engineered fuel, but it seems to have solved my problem.
After taking my yard machines push mower to the local mechanic he showed me a couple of tricks. Some push mowers have a tiny "starting " jet a cold and hot jet. He pulls the carb jet and uses a welder tip cleaner tool to poke through or clean the carb jet. Second dropping the carb float bowl and cleaning it out as well. Checking the gao on the plug, and blowing out the air filter or replacing it.
 
I've always had a hard starting craftsman tractor. I added an iridium sparkplug and started using Berrymans B12 in the gasoline. Since then,it starts almost immediately without any choke.
 
The auto choke was working...it closed when cold, and was wide open when warm.

Running engineered fuel long term is not an option. It would be cheaper to just buy a new mower that would run on regular gas ;-)

I understand what you are saying about the choke, but I'd change the parts anyway. The thermowax is a known problem. Youtube is fulled with videos about it. Here is one such example...

 
I repowered my Snapper Commercial mower with a Honda 190. It is a bear to start at times. I finally adjusted the choke mechanism, which is probably not the best design, to get a better "choke" when cold. Now it starts on the 4th or 5th pull and not the 30th.
 
I was gonna say if the carb has a filter you can pull to pop a little spray right in the top?

I’ve found ether or oddly standard seafoam will make it start added to the intake after the filter
 
Your gas might be old or degraded.

If your gas can is the old style that has a vent, get rid of it. These old style cans destroy the quality of fuel by letting the can vent daily. You want one of the new EPA cans that will blow up like a balloon if left in the sun. Keeping the vapors IN the can is good for long term quality of the fuel.

Also, date your fuel with some blue painters tape and a marker on your fuel can. When it gets 3 months old dump it in the car and replace it.

If the gas is fresh, it’s definitely that thermowax choke thing.
 
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DriveHard - you say the choke is working, but is it slapped completely shut? Like zero gap around the edges. I've seen several small engines where the choke plate is closed, but not 100% tight and this makes the difference between an easy starting engine and a very difficult one.
 
I had a 1998 3.8 Buick that ran like crap, GM couldn’t find anything wrong because they would have had to repair the engine under recall.

Turns out the plastic had a slow leak so it chugged coolant, added MMO and it ran normally 30,000 miles until the engine blew.

2 stroke and MMO helps with low compression under specific circumstances.

If everything else is terrific you might have a sloppy engine, it happens.
 
I understand what you are saying about the choke, but I'd change the parts anyway. The thermowax is a known problem. Youtube is fulled with videos about it. Here is one such example...


Why did honda go with this goofy design? I've never heard of "thermowax" before this
 
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