To much oil? Or carburetor issue?

Thomas1971

Thomas1971

Member
Hey everyone. I just got done building a new Raptor 4 the other day. All new parts and everything is to spec, When I run it, it spits and sputters blue smoke and there is a wet black gas/oil mix on the end of the pipe. I can’t tell if it’s oil or gas or both... I’m running 24oz of oil in it, flat mounted on my engine table right now. It will be flat mounted in a mini bike once I solve this issue.... Am I running to much oil? My other 2 Raptors run 24oz with no issues. Or am I having a carburetor issue? I have the EC VM20 with an EC manifold, sold as a kit. I should also mention the spark plug , Champion CJ-8, is wet and black in the center, running 87 octane gas, and Lucas full synthetic 10w-30 motorcycle oil.
 
OVALTECH1 said:
14-16oz of oil is plenty. You may have a carb issue as well by the sooty plug.
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Yeah once I change the oil and put in the appropriate amount I’ll try tuning the carburetor. It’s been impossible to tune with it sputtering and burning oil. Thanks
 
being it is flat mounted, i would use more then 16 oz, you should have a dip stick or a mark to show the full line, the flat mounted part is what most missed in your posting.
 
We run 14 ounces in our flatheads on a 15* mount, and 12 ounces in all of our flatheads on flat or 5* mounts.
The reason that we run more oil with an angled mount is that the oil polls up at the front of the block more, where the dipper cannot reach it.
Realistically, it simply drains back there, as anything past an idle on a flathead - the oil is mostly in suspension being whipped around inside the crankcase. A lot of moving parts moving in various directions. I still have a clear plastic sidecover here that we did testing with many moons ago.

If you were to check the oil level on a flat mount, it should cover the bottom thread of the front oil fill plug per factory specs. With a 15* mount, it will just start to run out of the front oil fill plug.

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🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
31 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
CarlsonMotorsports said:
We run 14 ounces in our flatheads on a 15* mount, and 12 ounces in all of our flatheads on flat or 5* mounts.
The reason that we run more oil with an angled mount is that the oil polls up at the front of the block more, where the dipper cannot reach it.
Realistically, it simply drains back there, as anything past an idle on a flathead - the oil is mostly in suspension being whipped around inside the crankcase. A lot of moving parts moving in various directions. I still have a clear plastic sidecover here that we did testing with many moons ago.

If you were to check the oil level on a flat mount, it should cover the bottom thread of the front oil fill plug per factory specs. With a 15* mount, it will just start to run out of the front oil fill plug.

-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
31 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
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Thanks for the advice. I have the Burris side cover, so I don’t have a lower oil fill plug. Just the top fill plug. So it’s kinda hard to check the oil. So I use a ratio right cup to measure the oz’s. I’ll try running 15 oz of oil and see if it stops burning it and sputtering.
I got 24oz’s by measuring how much went into my older 4 hp Briggs,(same block), But I filled it to the top thread of the bottom fill plug, while it was sitting flat.
 
Check the diaphragm gasket on the carb... If missing or worn out the engine will spit fuel out of the exhaust
 
Thomas1971 said:
Thanks for the advice. I have the Burris side cover, so I don’t have a lower oil fill plug. Just the top fill plug. So it’s kinda hard to check the oil. So I use a ratio right cup to measure the oz’s. I’ll try running 15 oz of oil and see if it stops burning it and sputtering.
I got 24oz’s by measuring how much went into my older 4 hp Briggs,(same block), But I filled it to the top thread of the bottom fill plug, while it was sitting flat.
Click to expand...
I think it stated 12 oz for flat mount??? Why would you use 15?
 
White smoke is always oil, black smoke is always Unburnt gas. On cold cold mornings them white puffs coming out of the exhaust are steam.
 
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Thomas1971 said:
Hey everyone. I just got done building a new Raptor 4 the other day. All new parts and everything is to spec, When I run it, it spits and sputters blue smoke and there is a wet black gas/oil mix on the end of the pipe. I can’t tell if it’s oil or gas or both... I’m running 24oz of oil in it, flat mounted on my engine table right now. It will be flat mounted in a mini bike once I solve this issue.... Am I running to much oil? My other 2 Raptors run 24oz with no issues. Or am I having a carburetor issue? I have the EC VM20 with an EC manifold, sold as a kit. I should also mention the spark plug , Champion CJ-8, is wet and black in the center, running 87 octane gas, and Lucas full synthetic 10w-30 motorcycle oil.
Click to expand...
you should run about 12oz oil.That much in one you are losing power,
 
Thomas1971 said:
Hey everyone. I just got done building a new Raptor 4 the other day. All new parts and everything is to spec, When I run it, it spits and sputters blue smoke and there is a wet black gas/oil mix on the end of the pipe. I can’t tell if it’s oil or gas or both... I’m running 24oz of oil in it, flat mounted on my engine table right now. It will be flat mounted in a mini bike once I solve this issue.... Am I running to much oil? My other 2 Raptors run 24oz with no issues. Or am I having a carburetor issue? I have the EC VM20 with an EC manifold, sold as a kit. I should also mention the spark plug , Champion CJ-8, is wet and black in the center, running 87 octane gas, and Lucas full synthetic 10w-30 motorcycle oil.
Click to expand...
Hey did you ever solve the problem? Because my engine has the same symptoms.
 
661_Minis said:
Hey did you ever solve the problem? Because my engine has the same symptoms.
Click to expand...
No I haven’t solved the issue yet. Haven’t had the time to work on it, I reduced the amount of oil to 16oz. And ran a pcv valve for extra crankcase ventilation. But it still doing the same thing. So I think it’s my ring end gaps are set to large, I need to double check that.
 
Thomas1971 said:
No I haven’t solved the issue yet. Haven’t had the time to work on it, I reduced the amount of oil to 16oz. And ran a pcv valve for extra crankcase ventilation. But it still doing the same thing. So I think it’s my ring end gaps are set to large, I need to double check that.
Click to expand...
Your problem shouldnt have been as bad though since you took it down to 16 from 24 but try 12-14oz. I saw something about a pcv on a motor like this but I wanna say they said it isnt a true pcv for a motor like these.
 
MO Predator Racer said:
Your problem shouldnt have been as bad though since you took it down to 16 from 24 but try 12-14oz. I saw something about a pcv on a motor like this but I wanna say they said it isnt a true pcv for a motor like these.
Click to expand...
The issue wasn’t as bad after I reduced the oil amount, at idle. But I did run it on my mini bike with the changes, and it still sputters and smokes bad…I’m taking it apart and remeasuring everything, hopefully in the beginning of next year. I’m going to try a different carburetor also.
 
Thomas1971 said:
The issue wasn’t as bad after I reduced the oil amount, at idle. But I did run it on my mini bike with the changes, and it still sputters and smokes bad…I’m taking it apart and remeasuring everything, hopefully in the beginning of next year. I’m going to try a different carburetor also.
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You should try replacing the coil. I was having the same problems with my raptor on my mini bike and fixed the problem by changing the coil.
 
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