Honda 2 hp outboard kicks back violently at pull start.

Hi all!
I apparently have had this problem occasionally for years but never really paid attention to it.However, this autumn the problem became very serious. Last time I had a very hard time starting the motor, badly injured my hand, etc.
I looked over the internet and found out that indeed it is a quite common problem with 2 hp Honda. Most people say it is either a problem with decompression valve or exhaust intake valve timing.
Ok, probably.
But I still cannot get it. To jerk the rope with the handle out of your hand the motor should start rotating in the opposite direction. Is it ever possible? And is it possible due to a problem with the decompression valve or timing?
Thanks for all suggestions!

Sounds like pre-ingnition. A timing issue is my guess.

I have a Yamaha generator that does the same thing, pretty much guaranteed to hurt your hand on the second pull if you don't roll the engine past the compression stroke with the rope before you yank it hard.

Quote:

---

Sounds like pre-ingnition. A timing issue is my guess.

---

Sorry, do you mean ignition timing?
Because, if I understood it correctly, pre-ignition usually means “diselimg”,”when the air/fuel mixture in the cylinder ignites before the spark plug fires”. https://en.wikipedia.org/wiki/Pre-ignition

Quote:

---

Originally Posted by dean.f

I have a Yamaha generator that does the same thing, pretty much guaranteed to hurt your hand on the second pull if you don't roll the engine past the compression stroke with the rope before you yank it hard.

---

Well, I’m not sure if I understood you correctly, but I’ve read a few times on the other forums the suggestion that you need to bring the crankshaft to the compression point (when you feel the resistance) and only then you should pull hard.
Is it opposite to what you are suggesting?
Thanks!

Quote:

---

Originally Posted by MarkD

Sorry, do you mean ignition timing?
Because, if I understood it correctly, pre-ignition usually means “diselimg”,”when the air/fuel mixture in the cylinder ignites before the spark plug fires”. https://en.wikipedia.org/wiki/Pre-ignition

---

It sounds like you are getting ignition (spark) before top dead centre for whatever reason. By timing, I mean you are getting spark too soon. I'm just guessing though.

Check that the spark plug gap isn't too small or carboned up. Check the woodruff key isn't sheared putting the flywheel out of timing. Put piston at TDC and check the timing alignment mark lines up correctly. Could put a timing light on to see what it shows if you get it firing too.

Thanks! Some of your suggestions are already done, some others will do.
Appreciated!

Quote:

---

Originally Posted by MarkD

Well, I’m not sure if I understood you correctly, but I’ve read a few times on the other forums the suggestion that you need to bring the crankshaft to the compression point (when you feel the resistance) and only then you should pull hard.
Is it opposite to what you are suggesting?
Thanks!

---

This is what I meant. I pull it until I feel the resistance from compression then let the rope back in and pull to start it.

Oohh.. I thought I already replied to that… But apparently I didn’t submit it…

I was actually doing this intuitively before and it seemed to work previously but not anymore.
I now took a look inside the combustion chamber and it’s full of the black deposits.
I would certainly prefer to find a solution without disassembling the engine, at least to try it first. I hope a new plug and cleaning the chamber will help.
What is the best way to clean the chamber though? There are at least a couple products, like Intake Valve & Combustion Chamber Cleaner and Sea Foam. But they all seem to be designed for bigger engines.
Is it Ok just to spray this stuff into the engine through the air intake of the running engine?

I’d get rid of the motor before you trash your rotator cuff. Trust me, it sucks . Leave it on your boat in the driveway and some dick will steal it within a day. You can then giggle, knowing that some thief tears his shoulder out the first time he uses it.

Well, honestly this is not the advice I was expecting even though I came across similar opinions about this motor.
However, the motor was built in 2001 and I got it about 12 years ago and it served me quite well for this time. Yes I got some kick back occasionally but even didn’t think that this is a problem but rather thought this is normal behavior for the recoil starter. Only recently it became really bad and I decided to take a look at it.
I hope it will start better after minor tuneup, cleaning the combustion chamber, crankcase etc.If not I may take some time to dig deeper into it. … Or may leave it as is… At the end, with good thick gloves, the rope attached instead of the handle and a bit of Quick Start I still can start it without badly snapping my hand.

Silly question ; Have you contacted Honda regarding this issue ?

It sounds like you have a timing issue. There are alot of different ways that timing can be effected.
You don’t mention if the engine is a 2 or 4 stroke.
Assuming the engine is mechanically ok and a flywheel sheer key is good, i would go with the carbon removal additive.

With respect to seafoam, its great stuff to remove carbon. Another excellent product is mercury power tune(better).
Start the engine and start to slowly spray the stuff into the intake. It will smoke like crazy but the carbon will be removed. Once complete, use seafoam in the fuel so it continues to work over time.

Ohh, sorry, I assumed that it is well known that Honda 2 HP is 4 stroke (as all other 2 HP motors).

Quote:

---

Assuming the engine is mechanically ok and a flywheel sheer key is good, i would go with the carbon removal additive.

---

I think if the motor is working normally after I am able to start it, I assume it is somehow ‘mechanically OK'.
The flywheel key is good.

Thanks, yes, this is what I intend to do. Just waiting for warmer weather to get the motor outside and smoke up a bit.

I wonder if the heat range on the spark plug is correct ? I'm guessing Honda's come with NGK plugs as OEM ? I use to own a VW Beetle and if I used anything other than Bosch spark plugs it ran like crap.

I’m not sure about the heat range of the spark plug I have in the motor, but I assume that if it was running well for years with that plug, it should be OK.
Yes, it is an NGK plug.
I have to admit that I haven’t changed it for a while, so it’s time to change.

As for the overall impression of the motor I would say that it served me well over a decade without much trouble. The only ugly thing about the motor is that it is quite messy, it is always oily all around. I wouldn't expect this from the fancy Honda brand but it is.
I recently found that the oil comes from around the short tube connecting the crankcase and air filter. It’s called a ‘breather tube’. I don’t know whether it is supposed to be like that or there is some solution for that. Any suggestions?
Ohh, and another cons for this motor is that the oil change is an extremely messy job. It is definitely a design issue which should not be in the Honda name. I’m not sure if they had changed it in later versions.

Have to ask, are you using hit test gas?

Hmm... Have no idea what's that... Or you just kidding and my sense of humor not good enough

No, no humour, high test gas, higher octane, it burns slower and causes carbon fouling and build up in low compression motors. I would pull the head off and clean the top of the piston and inside of the head.

Too much oil in crankcase can cause problems. Physically removing carbon build up by removing the head is a tedious job and great care must be used so as not to nick or scratch the metal and if you have to clean the piston head even greater care must be used to avoid debris inside chamber.

No, I always use regular 87 gas. I'll try SeaFoam first in the fuel and oil then will see if it makes any difference in running and visually on the piston head.

Quote:

---

Originally Posted by MarkD

No, I always use regular 87 gas. I'll try SeaFoam first in the fuel and oil then will see if it makes any difference in running and visually on the piston head.

---

Lots of information on here about this topic and even a few talking Honda engines May 20 ...

https://ontariofishingcommunity.com/...able/#comments


Pure-gas.org - ethanol-free gasoline in the U.S. and Canada

Ok, here is an update on the situation with the motor.
I had put a proper amount of SeaFoam in the oil, some amount in the fuel tank, then even put some in the combustion chamber ... Let it sit for a couple days…
After that it became very difficult to start the motor. I have to pull the rope about a couple dozen times before it would start. Surprisingly, Quick Start does not help at all.
Spark plug seems to fire well though.
I had run the motor with all this SeaFoam in the fuel and then put quite a bit of it in the carburetor through the air vent while running the motor on low and medium RPM.
The problem with this using SeaFoam or similar stuff on this motor is that it is not possible to spray it in through the air intake, because air filter intake pointed downside and the screws holding air filter also hold the carburetor itself, so it is not possible to remove air filter without dismounting the carburetor.
I also could not run it at high RPM because despite the motor itself being air cooled, the lower unit is actually water cooled and gets hot quite fast. So I put the lower unit in the bucket of water but couldn’t run it at high RPM due to water splashing.
I did not see any bit of excessive smoke running the motor with SeaFoam in the gas and carburetor. After that I removed the plug , looked inside the combustion chamber and could see that the piston remained as dirty as it was before. Apparently, SeaFoam helped nothing to the engine.
So I did all of that but the motor is still very difficult to start. I did not change the spark plug as I initially had ordered the wrong ones and am awaiting for the new ones now.
However, after I am able to start the motor it runs quite well even on very low RPM.
As for the kick back problem I’m not sure for now if it became better or not. Last couple times I started the motor I did not experience that but not sure if it is just accidental luck.
Now, if a new plug won’t help me with the difficult start I really don’t know what to do. Ignition timing is not adjusted on this motor: the ignition coil is attached to the motor with two screws and while it is possible to move it closer or further to the flywheel, it is not possible to move it along the flywheel to adjust the timing.
Any suggestions on that?
Thanks!