How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Hank F. Your Own Question
Hank F.
Hank F., Technician
Category: Small Engine
Satisfied Customers: 14411
Experience:  Certified on Onan and Generac generators
Type Your Small Engine Question Here...
Hank F. is online now
A new question is answered every 9 seconds

I have a onan p216 and I am getting oil spitting from the

Customer Question

I have a onan p216 and I am getting oil spitting from the backside of the fuel pump
Submitted: 6 years ago.
Category: Small Engine
Expert:  Hank F. replied 6 years ago.


What is the full model number of your engine?

There are more than 1 version of the P216.


Customer: replied 6 years ago.
HI, the model #is P216G 17112BOE...I checked the compression and its about 118 on one cylinder and about 119 on the other, I checked the packing on the riser tube from the crankcase for obstructions and there were none, the engine only has 498 hours on it, its a 2004 model, and has no smoke in the exhaust that I can see, and runs great other than the small amount of oil spitting from the back of the fuel pump
Expert:  Hank F. replied 6 years ago.

On the back of the fuel pump is a piece of hose that is either 7" or 10 1/4" long, depending on which block this engine uses. This is the fuel pump pulse line, and is where the oil is coming from.


Only 3 things will cause oil to get into this line:

1. The engine is/was overfilled with oil.

2. Too much crankcase pressure, caused by either packing in the breather being full of oil (simply clean the packing in solvent), or bad rings allowing exhaust blow-by. The cylinders can show good compression but still be allowing blow-by. Only a leak down test can determine if the rings are at fault.

3. The unit has been operated on too steep of a slope, allowing oil to get into the line.


Check the oil level to ensure it is not overfull.

Remove the pulse line from the engine and thoroughly clean it out.

If oil still continues to get into the line, you will probably need to have a leak down test performed on the engine to determine if the rings are at fault.


Customer: replied 6 years ago.


HI, on top of the packing is a removable cap that has 4 holes in it, 3 of which have a, what looks to be a neoprene ball in it, and one of the holes is open with no ball in it, could this be the problem? the packing looks as good as new, and I just changed the oil and put 1.75 qts including the filter which is what the manufacturer states is the correct quantity.... I have no way of performing a leak down test, if it is indeed the rings, how hard is it to replace them?

Expert:  Hank F. replied 6 years ago.

One of the balls missing would not cause this. It's when the balls stick and can not move that would cause it.

Even though the book says 1.75 Qts, you still need to go by the full mark on the dipstick. Make sure the oil level is not over this mark.


Replacing the rings is a pretty big job. But with only 500 hours on the engine, this is actually one of the least possible issues.


What I would suggest at this point is to first check the oil level.

Then I would remove the pulse line from the fuel pump and engine, and clean it out good.

Then I would monitor it for a while.

It is possible that the crankcase had gotten overfilled at one point, or if the unit was run on a slope, it could have gotten oil into the line. Once oil gets in there, it stays until you clean it out.

If it continues to get oil in it, then you may consider having a leak down test done on it. I definitely would not go through the expense of replacing the rings without having first done a leak down test.


Customer: replied 6 years ago.
HI, I replaced the cap on the packing with one from a blown engine and it no longer spits oil, I run it for 3 hours at full throttle and not a this WAS the problem....I cannot be satified with your answers since I solved the problem myself and you actually told me this could NOT be the problem, it seems the crankcase couldnt achieve a correct negative pressure with one of the balls missing, thats all I did and it no longer spits, so I have to assume that it was the problem..Thanks for your help

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
< Previous | Next >
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland

Meet The Experts:

  • Curtis B.

    Curtis B.


    Satisfied Customers:

    have worked on and around most engine models for 35 yrs./Polaris ATV expert
< Last | Next >
  • Curtis B.'s Avatar

    Curtis B.


    Satisfied Customers:

    have worked on and around most engine models for 35 yrs./Polaris ATV expert
  • Rick's Avatar


    Factory Authorized Trainer

    Satisfied Customers:

    Outdoor Power Equipment technical trainer since 1990, covering eight states.
  • Jon K.'s Avatar

    Jon K.

    Small Engine Diagnostic Expert

    Satisfied Customers:

    Gold certified Stihl tech, Service Manager for a rental/repair shop.Certified in most small engines
  • James W's Avatar

    James W

    Small Engine Troubleshooting Expert

    Satisfied Customers:

    7 years as Mechanic & Parts Manager for Brother who has Owned Lawn & Garden Repair shop for 35 years
  • Vince O.'s Avatar

    Vince O.

    Small Engine Technician

    Satisfied Customers:

    Over 30 years experience repairing lawn and garden equipment. Chainsaws, mowers,blowers and trimmers
  • RUSS's Avatar



    Satisfied Customers:

  • Wayne's Avatar


    Engine Rebuilder

    Satisfied Customers:

    many years on egine rebuilding, lawn mower,roto tiller,Truck,and small engines