low power

[BoltsMissing]

So here's my question to everyone, If it's not the carb, what else would cause the loss of power symptom?

1.Exhaust pipe gasket not matching oval shape exhaust port hole, or leaking.
2.Carby manifold gasket not matching intake port hole, or leaking.
3.Spak plug gap/Spark plug brand ( try using NGK B6HS, GAP:0.025, experiment though, some say less, others say more.)
4.Plug lead, use other copper lead than HT.
5.Plug cap, try NGK plug cap Part No.: LB05F, 5K OHMS
6. Bad/loose connections to CDI. Do you have standard HT kill switch conected ?
------,
7. Oil/Fuel mix ratio, what ratio are you using ?
8. Fuel type, I use 95 octane, 98 ran sick, 92 ran sicker.
9. dirty air filter "element"/ sponge.

 

[crabdance]

Hi BoltsMissing,

Thanks for all the feedback. I will have to check most of these things and find out what state they are in. You've been a big help and I thank you. I will check this stuff out later on today and let you know what's going on with them.

cd

1.Exhaust pipe gasket not matching oval shape exhaust port hole, or leaking.
2.Carby manifold gasket not matching intake port hole, or leaking.
3.Spak plug gap/Spark plug brand ( try using NGK B6HS, GAP:0.025, experiment though, some say less, others say more.)
4.Plug lead, use other copper lead than HT.
5.Plug cap, try NGK plug cap Part No.: LB05F, 5K OHMS
6. Bad/loose connections to CDI. Do you have standard HT kill switch conected ?
------,
7. Oil/Fuel mix ratio, what ratio are you using ?
8. Fuel type, I use 95 octane, 98 ran sick, 92 ran sicker.
9. dirty air filter "element"/ sponge.

 

[BoltsMissing]

crabdance
Most of this info is scattered around the forum by many members contributions.

 

[MotorMac]

fuel filter?

Sounds to me like a clogged fuel filter,check the little screen in the fuel shutoff valve coming out of the bottom of the tank, theres a small screen it there you can throw away and replace your inline filter if you have one. Hope thats all it is. 95% of the time thats all it is on the large marine engines I work on.

 

[crabdance]

Hi MotorMac,

Thanks for telling me about that one. I will check that out tomorrow and see if that's it. That would be great if it is. That would be much better than being something wrong with the engine that's for sure. I will let you know how things turn out tomorrow.

cd

Sounds to me like a clogged fuel filter,check the little screen in the fuel shutoff valve coming out of the bottom of the tank, theres a small screen it there you can throw away and replace your inline filter if you have one. Hope thats all it is. 95% of the time thats all it is on the large marine engines I work on.

 

[crabdance]

1.Exhaust pipe gasket not matching oval shape exhaust port hole, or leaking.
2.Carby manifold gasket not matching intake port hole, or leaking.
3.Spak plug gap/Spark plug brand ( try using NGK B6HS, GAP:0.025, experiment though, some say less, others say more.)
4.Plug lead, use other copper lead than HT.
5.Plug cap, try NGK plug cap Part No.: LB05F, 5K OHMS
6. Bad/loose connections to CDI. Do you have standard HT kill switch conected ?
------,
7. Oil/Fuel mix ratio, what ratio are you using ?
8. Fuel type, I use 95 octane, 98 ran sick, 92 ran sicker.
9. dirty air filter "element"/ sponge.

I tried most of the stuff on here and everything was alright. I still need to check the connection on the CDI and the kill switch but I will get to that tomorrow. Thanks for all the help man.

cd

 

[MotorMac]

update

Keep us updated as to what you find, if its not a fuel related problem then its either electrical or mechanical,, try bypassing the kill switch altogether, connect the blue wire from the CDI directlty to the blue wire coming from the engine and connect the black to black wire, cap off the white wire completly. make sure nothing is grounding on any part of the bikes frame.If it runs with full power then that would have been the problem.
If that fails to give you full power then you need to check compression, take the spark plug out and put your thumb over the hole, have someone turn the pedals you should feel a strong pulse, if its weak or no pulse then its time for a new engine or new set of rings,.

 

[Maxx Ported]

The upper tube in the muffler, may had collasped, causing a restriction...this one was rattling, before it lost power.

 

[crabdance]

minor update

Ok here's a minor update; I took off the petcock valve yesterday and it was full of stuff so I cleaned it out. I could not find a filter so I guess it was already taken off (I got this engine second hand). Anyway, it didn't make a difference in the way the engine ran. My next thing I'm going to check is the inline filter and make sure that it's not plugged up too bad. If that's not the problem then we will move on to the other things..

thanks for the help everyone..

cd

 

[wayde]

Ok here's a minor update; I took off the petcock valve yesterday and it was full of stuff so I cleaned it out. I could not find a filter so I guess it was already taken off (I got this engine second hand). Anyway, it didn't make a difference in the way the engine ran. My next thing I'm going to check is the inline filter and make sure that it's not plugged up too bad. If that's not the problem then we will move on to the other things..

thanks for the help everyone..

cd

you could almost rule everything but the carb out since the problem came about when you switched carbs, here's a thought for ya, take the prongs out of your old carb and put them in the new carb, your new one will likely start to leak and your performance should come back on the same note take the prongs from your new carb and install them to the old carb and see what happens, if you switch them and the old prongs in new carb work better but still leak then you have to adjust the prongs just until it stops leaking BUT if the new prongs in the old carb work better then it prolly has a larger jet and you basically just changed the jets (the new prongs should stop the leak) if performance is poor then your left with no other choice than to deal with a leaky carb and great performance or taking the leap and adjusting the prongs