6.5 engine probs

[Shauns]

Ok I have been trying to upload a video for you to have a look and the internet is so dam slow here it will not do it . I will keep trying , Last night I pulled everything off it carbie , electrics etc. cleaned everything and put it all back together and that's now 2 hours of my life gone . thinking just easier to buy a new motor . So now I have a question about motors , the go-kart is built really solid and I am worried 6.5hp may not even be big enough . Now I have no way to weigh the gokart . Whats every ones thoughts on power to weight ?
I would prefer the 6.5hp mainly because I have a brand new clutch to go on that suits the shaft on the 6.5hp so if I went to a bigger HP they seem to have bigger shafts.

 

[KartFab]

6.5 is one of the most common types of small engines. Sorry to hear you didnt figure it out. I cant really help much but here is what is running through my head right now.

basically, engine needs
fuel
spark
air

most common problem is bad gas and a clogged carb, which doesnt give u much fuel. Could be a number of reasons, but if your engine runs poorly our out of wack, and you have spark, it could mean that your timing is off (almost exclusively caused by sheared flywheel key, you can pull the nut off with an impact wrench and make sure it isnt sheared).

not enough air would be an issue with the air filter, so if you run it with air filter vs without, you could weed it out. minor problems with air would be leaky gasket AFTER the carb (so carb to engine- making it run lean but based on your spark plug issue, almost sounds like it runs rich? If it runs super super rich you get lots of smoke and poor performance. Did you check the jet to see if it may have been tampered with?

My gut feeling judging from all the rust on that engines muffler and tank is that it has been out in the weather and is really old. Leaving an engine outside for such a long time can cause a lot of rust to happen, especially if it has a valve partially open when it is stored. You would need to 'test' for compression by taking off the flywheel cover and just turn it over by hand, you should really feel the flywheel want to bounce back fast as it is coming into the compression stroke as you turn it over. If you take the plug out, you will notice it spins freely, but with plug in it shoudl still spin freely until it starts building compression. If you still get it spinning freely as you rotate it by hand, you might have an issue there with valve seals and ring seals.... it just looks very worn out though so it could be other issues that you cant see and are not easily diagnosed.

 

[Shauns]

yes it does look like its had a long life , I am going to have a real good play with the carb tonight and then off to the dump with it well not to the dump but will pull it completely apart once I buy a new one just so I can get to know what the inside looks like . Thanks for all the advice everyone it been great .

 

[Shauns]

very late update , I had lost interest in fixing it but on the weekend I decided to have another play , had a look at the valves made some adjustments and now shes a goer again

Now to do some research and find out what the valves are supposed to be at because I just took a guess , First attempt it would not start at all second attempt I was cruising

 

[Poboy kartman]

Nice!!!IIRC....KartFab gave you that as a possible problem.

 

[Shauns]

yeah , I didn't have a clue on what to look for but on the weekend I bit the bullet and did a compression test and all was good so it only left one more thing the valves . I didn't realise it was just the 4 bolts I had to undo and booom there they are lol

 

[Shauns]

Anyone know the correct setting on these valves , its hard when I don't even know the brand , it is some kind of copy I presume . It was running off measurements that I guesses , so I though I should do it properly and found some measurements on the net but now it will not start I did inlet .004 and exhaust .008

 

[Poboy kartman]

Anyone know the correct setting on these valves , its hard when I don't even know the brand , it is some kind of copy I presume . It was running off measurements that I guesses , so I though I should do it properly and found some measurements on the net but now it will not start I did inlet .004 and exhaust .008

Just to be sure....(because it should run with those) ....You WERE at TDC on COMPRESSION stroke when you set them....

If you were on exhaust...it's not likely to run.

If you've adjusted the valves correctly....then it was just coincidental the first time....But!!! What's right there at the valve cover? ???? Could be a bad spark plug wire getting bumped around and making connection and then not!

 

[Shauns]

Will double check but pretty sure I was , I will give you an update tomorrow . , I will have another play with it .