Clank/smack when engine starts

[RandyNavarro]

I have old Yerf Dog - 150cc GY6 engine. Been having troubles all summer long but slowly working them out. Here's the latest:

When starting/turning over there is a good sounding CLUNK or CLANK that sounds about every other start. When it CLANKS, it sounds like it dies and the engine doesn't wants to turn over but then starts up and runs fine.

I just replaced the starter today but it didn't fix the problem.

If it's useful information, I've been having some electrical problems but those may be worked out now--not quite sure but we'll see.

Any thoughts?

 

[landuse]

I have old Yerf Dog - 150cc GY6 engine. Been having troubles all summer long but slowly working them out. Here's the latest:

When starting/turning over there is a good sounding CLUNK or CLANK that sounds about every other start. When it CLANKS, it sounds like it dies and the engine doesn't wants to turn over but then starts up and runs fine.

I just replaced the starter today but it didn't fix the problem.

If it's useful information, I've been having some electrical problems but those may be worked out now--not quite sure but we'll see.

Any thoughts?

Does it sound as if it is coming from inside the engine, or maybe from the drivetrain?

May post a short vid for us to hear?

 

[Karttekk]

The GY6 engine uses a clutch or sprag with their starters. It will only turn one way. When you turn the key to start the engine the starter gear engages the clutch and rotates the engine. Once it starts the clutch just freewheels. You may have some issues with this clutch. The engine cover has to come off to access it and it takes a special left hand thread puller to remove the flywheel. Without hearing it, this is one thing to consider.

Thanks

 

[Karttekk]

Go to page 46 in this manual if you decide the starter clutch is the problem.

https://americanlandmaster.com/pdfs/LUTV/150cc-service-manual-14589R4.pdf

Thanks

 

[RandyNavarro]

The GY6 engine uses a clutch or sprag with their starters. It will only turn one way. When you turn the key to start the engine the starter gear engages the clutch and rotates the engine. Once it starts the clutch just freewheels. You may have some issues with this clutch. The engine cover has to come off to access it and it takes a special left hand thread puller to remove the flywheel. Without hearing it, this is one thing to consider.

Thanks

Yes. This sounds like it might be the case and also the area from which the CLANK is coming from.

I'll check the document and do some troubleshooting.

Thank you very much!