Mount field HP470 hunting

[ipbr21054]

Hi,
Just picked up a Mountfield HP470 for free.
I starts but didn’t Rev up just Hunted.
I’ve cleaned up the throttle bracket plate as it couldn’t move & also the engine stop bracket. Now both are free.

With the air filter box off I can see a small lever moving. This lever has two springs on it. One spring goes to a metal bracket which I don’t see moving at all.
If I move the bracket myself the engine the reva higher.

spring is rusty and just snapped on me.

can you advise on this issue.
Maybe also show me on the metal bracket where the spring should be hooked onto as maybe it wasn’t in the correct place to start with.

see if this video clip helps you.
https://drive.google.com/file/d/1AmGe-gIqFEzPyQnN9DRl1Nw8ZPa5bPa4/view?usp=drivesdk

 

[Burnerman]

Can't access the video I'm afraid....can you try something else?
John

 

[ipbr21054]

try now please

https://drive.google.com/file/d/1AmGe-gIqFEzPyQnN9DRl1Nw8ZPa5bPa4/view?usp=sharing

 

[Burnerman]

OK, I have the video now.
The white lever coming from under the fan cover is the air vane governor......the blast of wind that controls it directly comes from the cooling fan. It's a bit hit and miss but works well enough usually.
The thin spring is in the correct position, the rusty other spring is too - but it's length should be in the region of 75mm long...it's a fine tension spring maybe 6mm in diameter.
These engines normally have a throttle lever and cable - the end of which goes into the lower bracket of the two here. The incorrect spring is held lightly under tension when the throttle lever is on full.
Is it missing on this machine?
John

 

[ipbr21054]

The small spring is fine so i will leave that.

The rusty spring just snapped so a new one has been ordered so at least i know the hole it goes in.

The only leve is the one you let go to then grab the spinning fly wheel and for it to stop.

There is no throttle cable or lever so maybe it was taken off ??

The vertical handle bar does have a hole in the same position as the engine stop & also say 4 holes going down the shaft handle.

Do you think its just the lever / cabcle missing ?

When would it connect to on the the carb though ?

 

[ipbr21054]

Just looked at a pdf fil and no throttle lever etc is shown for this model

 

[Burnerman]

Ok, if its a constant speed model then replacing the spring should help it - together with moving the bottom lever fully clockwise if it will move.
What I would do is:
Check the fuel tank for debris and rust;
Remove the carb (5 screws) and check the dip pipe for crap in its filter;
Replace the gasket and diaphragm with a genuine Briggs item.
John

 

[ipbr21054]

Looking at attached photo cn you advise which to bend.

also that bracket can move anyway. see video clip.

https://drive.google.com/file/d/1HOiekQXLXH8f9ayhMLNxjTb2wNCKglaz/view?usp=drivesdk

 

[Burnerman]

The missing spring goes between the elongated hole and the loop on the governor rod connected to the air vane.
To get the engine to run fast - if there is no throttle cable fitted - the lever that you move in your video is turned clockwise. (Blue arrow). Perhaps it can be locked in place with that tag that you can see on the left, almost touching the air intake?
If it ever had a throttle cable, the end of it goes through the left hole on the blue arrowed bracket, and its outer would be clamped to the cylinder head.
See if you can get the engine to run smoothly and at a constant speed by somehow locking the blue arrowed bracket firmly.
John

 

[ipbr21054]

Ok
I will do that once the new spring arrives.

Thanks for your time

 

[Burnerman]

Most welcome!
Don't expect perfection here, the air vane governor ain't the best and governors are driven by the camshaft now. The carbs aren't adjustable (they used to be) but replacements are cheap.
I bet that motor needs an oil change!
John