Excessive carbon building up on plugs

['96 Charger]

I have a '96 Yamaha Pro V 200 that is throwing way too much carbon on the plugs. I'm running standard NGK plugs and Quicksilver Premium Plus oil in the oil tank. I ran Yamalube ring free in it earlier this year. Right now the only thing that seems to keep carbon from building up is keeping a heavy mixture of seafoam in the gas tank and that's expensive. Any type of plug and/or oil that might help? thanks in advance.

 

[seahorse5]

Re: Excessive carbon building up on plugs

3 things cause carbon buildup:

weak ignition system - will the spark jump a 7/16" gap

too much fuel and/or oil - check carbs and oil pump adjustment link

engine temp not warm enough - check thermostats and poppet valve operation

This is if all plugs build up carbon. If only certain ones do, then you need to check pump diaphragms (if applicable) and do a leak-down test, or at least a compression test, plus inspect that cylinders carb.

 

['96 Charger]

Re: Excessive carbon building up on plugs

It's on all plugs. Carbs just got rebuilt a couple monthis ago. You think it might be the ethanol loaded gas? Last time I got gas I was too lazy to go to the ethanol free station and got Premium e10 instead. The residue seemed to be a little sticky as well. I keep reading about people using spark testers. Where would be the best place to get one? My motor was a little tempermental this last time on startup but a short run a wot seemed to fix it.

 

[rodbolt]

Re: Excessive carbon building up on plugs

use of premium fuel in that engine also leads to carbon build up.
87 is fine 93 is a waste of money.

 

['96 Charger]

Re: Excessive carbon building up on plugs

Looks like I'll make sure to stick with stabilized ethanol free 87. Thanks guys.

 

[sdsaw]

Re: Excessive carbon building up on plugs

too much fuel and/or oil - check carbs and oil pump adjustment link

I'd be checking for too much oil that's being injected rather than the fuel

 

[seahorse5]

Re: Excessive carbon building up on plugs

It's on all plugs..

Have you tried different oils? Merc's Premium Plus is good oil but the metallic elements in it can leave hardened carbon deposits in some engines. If everything else checks out OK, pay close attention to oil pump adjustment and engine temp at idle, try the Yamalube 2M.