Fuel in engine oil

[redlowrey]

Mate you stated in your first post that the engine ran great, if you had injectors that were sticky or leaking the engine would be running like a dog. If you can smell raw fuel in the sump it is coming from an other sorce. Just make sure when you check the oil that you have the engine at the same level on the trim otherwise you will get a false reading on the dip stick. i bet they pressure tested and flow tested your your injectors and put them back in because there was nothing wrong with them.

[Peter Werner]

When oil has been checked engine was always in full-down position. Engine has always run well (only ~20 hours). Engine temp-hot was only 140F prior to changing thermostats - now ~160F with new stats. My concern was thermostats - Suzuki made decision to replace injectors as well. Will have to wait a couple of months to know results.

[captbill]

Making oil

Mr. Red Lowery's suggestion to check the "low pressure fuel pump" is your best and most convient bet.
I do not believe that you could get that amount of fuel in the oil in that number of (LOW) hours even if you had no piston rings.

In my own experience with (DF140's) that much oil is a fuel pump diaphragm puncture or an internal gasket/ O-ring.
The fuel pump on the DF140's is mounted in the cylinder head/Valve cover the actuator rod is bathed in the engine oil to the valves, a puncture or crack in the inner diaphragm will release a lot of fuel into the oil flow and the fuel pump gasket will assure that all of the fuel bypassing the pump gets into the oil.
This has happaned to me and to 3 other Zuke owners I personally know.
The zuke dealer probably checked the compression, the motor runs well.
It is not likely that Injectors or cold temps are to blame.
A good number of the commercial fisherman here on the Chesapeake are running automotive gas V8's with raw water cooling, The saltwater screws up the thermostats pretty qiuckly so they just remove them. Yes they get lower fuel mileage but I have never heard of one "Making oil" because they run cool.

If the if the Base, the mounting screws, or the actuator rod on the "low pressure" fuel pump on your motor is in contact with the engine oil, The fuel pump is most likely the cause.

Do not run your motor with the engine oil diluted with fuel that could lead to mental anguish and severe engine damage.

Ask your dealer to check the fuel pump diaphragm, or for about $ 25.00 U.S. you can replace it yourself, if that is not the problem you have a spare (It will break down sooner or later).
I doubt you will be dissapointed, and it could save you from losing some Yachting time

Mr. Lowery speaks truth.
Captbill

[Peter Werner]

Thanks again Mr Lowery. I understand IC engines (2c & 4c) reasonably well - however appreciate the advice of Xperts. Yeh - significant crankcase liquid increase. Drew down ~ 1qrt @ ~ 12 hrs, and high again @ ~ 20hrs. Suzuki dealer (good man) came to boat to verify increased crankcase level. Took boat to shop - completely checkout - no "functional" problems found - Suzuki did not advise shop to do anything other than the required 20hr service. Boat put back in water & slipped. I initiated formal complaint with Suzuki Customer Service -SCS then authorized shop to replace stats & injectors - that was done @ slip in mid-Nov - and then out for short test run for operation - all good. Engine will not be run again until early February. Others have suggested low-temp as a potential problem. I understand your opinion - lots of fuel passage simply due to low engine temp. We will have to wait until at least early Feb to know results. Thanks though for your feedback - all is valuable - it's how we learn. TC - Pete

[Harper]

Problem with the low-pressure fuel pump theory is that, unlike the smaller 4-cylinder motors, the low pressure pump on the DF300 is a rotary, electrically operated pump, just like the high-pressure pump. It is not the cam-operated diaphram pump as found on the DF150/175, et al. So that is not likely to be the cause of gas in the oil.

[Peter Werner]

Thanks Mike - All's valuable - we'll see in Feb - Pete

[Peter Werner]

Just ran engine (DF300) for a 2 + hour trip - first time since mid-Novemeber. Checked crankcase level prior to run. CC level increased by about 1/2 inch on dipstick after run. Apparently fuel still being introduced into crankcase at serious rate. To re-cap: Suzuki had service shop install new thermostats and all new injectors in November. Engine had been idle from then until this past 2+ hour run. Advised Suzuki today. Still interested in any ideas or of any other experiences like this. Thanks - Pete in Blaine, WA

[kmoose]

Have the oil changed at the dealer. Run the boat hard for 2+ hours recording documenting everything. After the run, take an oil sample and send it to:
Blackstone Labs

Once you have the results you can request a formal, written response from the Suzuki rep for your records when or if this problem continues. Remain calm and factual and demand responses in writing or email.

Like another stated, this is not a fuel pump problem as the LP pump is electric. I feel it has alot to do with the water temp in your area but like you I would be somewhat concerned as fuel accumulation in the crankcase does horrible things to the lubrication qualities of the oil.

[Peter Werner]

Thanks Kmoose, Engine oil was changed by dealer mid-Nov, sat idle on boat until Feb 10. Ran for 2+ hours - oil 1/2 above full. Dealer has oil sample from oil drawn at mid-Nov oil change. Have sent your suggestion to Suzuki CS and dealer. Will see what they say. Am keeping very good records. Will keep thread updated. Thanks again - Pete

[nelbur]

In my opinion, the dark colored oil along with the gain in volume is an indication that the problem comes from rings that are not yet seated. Combustion products and some unburned gas is being blown past the rings and condensing in the crank case. The higher temperature thermostat should help some by evaporating the gas, assuming that is the thermostat they put in. In my experience with my 140, once the rings seat the oil will stay clean and the level will stop rising. It took mine almost 250 hours to stop making oil completely, probably because I do quite a lot of trolling. The improvement was gradual, so it will likely soon be tolerable,especially if you run the engine fairly hard. I sucked the excess oil out with a Topsider when it reached about 1" above full, and when it reached 1" above full again I changed oil. If your oil, like mine, is 10W40, it can take some dilution and have fair viscosity. I believe you will be happy with the engine once it is broken in completely.

[Peter Werner]

Nelbur, Thanks - hope that's all it will be. Seems like quite a bit of pass through though. Suzuki tech support has a number of checks that the dealer is going to implement at thbe dock and underway this coming Wed (02/20). Will keep thread appraised. Pete

[Peter Werner]

Suzuki Proposal

Yesterday (02/20) Per Suzuki CS, dealer performed: compression check (all near 150psi), treated running engine with Sea Foam, then compression check again (all increased slightly). drew almost 1.33 quarts from CC.

Today (02/21) Suzuki advised me that they believe cylinder walls are glazed and have authorized dealer to hone cylinder walls and install new piston rings.

This problem started with only 8 hours on engine, and has gotten progressively worse - now about 24 hours on engine.

I want a new engine block installed - this is basically a new engine. Suzuki knows my position - so far they indicate the honing & new rings is all they will do.

Any advice out there? Pete

[redlowrey]

Never in fourty five years of engine rebuilding have I had an engine filling the sump with fuel from the cylinders being glazed. If that is the case why isn't oil getting past the rings into the combustion chamber and blowing smoke.

[Peter Werner]

Thanks again. I agree - should be burning oil as well. A Suzuki CS manager talked w/me today. They have offered to send their tech to dealer to do the work. They still insist that honing & re-ringing is the solution. I am still reluctant to let them take it down - and leave me with few options. Eventually I may need to hire an independent expert to represent me. Sucks - Pete

[Carpenter]

Not an expert however: decades ago super slippery oil like synthetic was not advised in new engines as there was concern the rings would not reliably seat. Any one remember breakin oil.

Also I once had a very expensive car hydrolock when a fuel injector o-ring leaked when engine was not running.