2019 DF300 Making Oil

[Triton2300]

Thanks for all the information from everyone. I have been reading about the VST issues on Suzuki’s and wonder how widespread it is. I have worked on old small outboards and have seen crystal clean carburetor float needle assembles from Evinrude Zephyrs, (1940’s)
1960s Johnson’s, and in-line Mercury’s tower of power. Suzuki should copy them like Yamaha copied OMC’a cross flow engines.
I will contact the Suzuki mechanic tomorrow and see when they can look at it. Hope it’s not too long but will report back when I know something. I know it’s time to get a manual and start getting my hands dirty again.

[Moonlighter]

One thing I will add, is that its really important to run a good water separating fuel filter between the tank and engine. Usually they go in line before the primer bulb.

Something like a Racor style filter. Suzuki here in Aus also sells them with a good German media filter for a very reasonable price.

Yes I know most people will have them fitted to their boats, but now and then it does emerge that an issue with dirty fuel arises and we discover that the filter isn’t fitted, or the element hasn’t been changed in some time.

So just a reminder about that.

cheers!

[Triton2300]

One thing I will add, is that its really important to run a good water separating fuel filter between the tank and engine. Usually they go in line before the primer bulb.

Something like a Racor style filter. Suzuki here in Aus also sells them with a good German media filter for a very reasonable price.

Yes I know most people will have them fitted to their boats, but now and then it does emerge that an issue with dirty fuel arises and we discover that the filter isn’t fitted, or the element hasn’t been changed in some time.

So just a reminder about that.

cheers!

I change mine (Racor) every spring or about 75 hours.

[Triton2300]

Update. I put in a service request and also texted the Suzuki Mechanic. He called me and said to try something before he comes over to the marina and charges me an arm and a leg. He first explained the C10 gage (fly by wire) that displays water temperature, displays the hottest condition. So if my gage is reading 140F, that does not mean that both sides of the engine are running at 140F. If one of the thermostats is stuck open and running at 110F and the other side is running at 140F, the C10 gage will read the higher number.
So I happen to have an infrared temp gun that I got at Harbor Freight for 25 bucks.. I am going to change the oil hopefully Sunday or Monday, put it in the water, and see what readings I get from one side and the other.

I did a seafoam treatment to the engine. (gallon of gas and a can of seafoam, let it idle, let it sit for 15 min, then start) Took it out and noticed the oil level dropped about 1/4 inch. Strange. Mechanic said change the oil and run it. If the level climbs again, he will come and troubleshoot VST etc...

[Triton2300]

Here is how far it dropped on the dipstick from the full mark

[Triton2300]

Update. I changed the oil and filter. Ran it 5 hours so far and the oil level has not changed. Good. Blackstone needs 5 hours on the oil to analyze but 10 is better. I will try for 10 to 15.
The Suzuki mechanic thinks because I did a Seafoam treatment this past spring, introducing a can of Seafoam mixed into a gallon of gas may have been too rich for the engine plus Seafoam does not burn that well. May have caused the mixture to slip past the rings into the crankcase. Not necessarily a bad thing because Seafoam will clean a crankcase also. If I do a Seafoam treatment I should check the oil level right after and be ready to change the oil.
I will keep the thread up to date. After 12 or 15 hours I will send a sample into Blackstone. Engine is running great. Comes right up to 6325 at full trim.

[Triton2300]

Got 10 hours on the new oil change. Sent sample in to Blackstone Laboratories Inc. Fuel dilution is 3.2 percent after 10 hours. Oil level did rise on the stick. I contacted the guy who works on it and have him check the thermostats and VST to see if that it the problem. Any other things to check?

[Triton2300]

I have a question. If I have this engine looked at by a certified Suzuki mechanic and he can’t find anything wrong, at what point does this become a warranty issue? I have a 6 year warranty on the engine. If I ran this engine a full 100 hours, the oil would be surely be mostly fuel and probably would not run very long.

[Triton2300]

The Marina I drystack the boat will not let mechanics work on outboards after 12/11/2021 so it kind of leaves me until the spring (April 1st). The Marina where its kept is only works on Yamaha outboards. I decided to give the Marina a call where I bought the engine and spoke to the service manager about the engine making oil. He said they have serviced quite a few Suzuki Outboards making oil and their main remedy has been running a heavy dose of ring free through the engine. He said they have also had issues with thermostats hanging open. He didnt recall any newer engines with VST issues. I then called the Marina where I keep it and spoke to the owner about the engine making oil. He said he will have his Yamaha mechanics change out the thermostats and inspect the old ones sometime in January/February. He didnt want to mess with the VST. I said do the thermostats and change oil. April 1st I will run ring free and run ten hours or more then submit to Blackstone Labs for analysis. If not fixed its on to the VST with the Suzuki mechanic. Its frustrating I could not get the certified Suzuki mechanic up there to go through the engine and diagnose it but I will get there one way or another. I will keep this post going for anyone with similiar issues. Thanks for all the replys.

[redlowrey]

I think you have a couple of cyls with the ring gaps lined up.

And every time the pistons with the ring gaps lined up come up on compression not combustion a very small amount of fuel that has condensed on the cylinder wall gets pushed past the rings into the crank case.

At 6000 rpm the injectors would be nearly on continuously, as soon as the inlet valve opens the fuel will be flowing in at a high rate. Some people think that it’s because the rings have not bed in, but these engines burn the fuel at around 14.7 to l when cruising and don’t burn oil.

Do a couple of trips and don’t go over 4300 rpm and see what happens on the dipstick, l think the rings will eventually spin and your problem will go away. If you are in a hot part of the country run 15w40.

[Triton2300]

Thanks Redlowrey. I will keep that under advisement.

[redlowrey]

I should have added you have an electric low pressure fuel pump so it can’t come from there,
and your engine is closed loop so if the vst was over flowing into the purge line it would effect the fuel trims and the check engine light would come on.

[Triton2300]

So in a closed loop fuel injection system a sensor would notice an incorrect amount of fuel (if fuel were overflowing into a purge line) and trigger a check engine light?
I also read a closed loop system has other variables that adjust fuel and one is the temperature of the engine. (Thermostats)
I will have to read more to understand different fuel injection systems.

[redlowrey]

All fuel injected engines monitor engine temp for injection pulse width. The strange thing is, why hasn’t your mechanic plugged in an sds and monitored the whole history of the engine, fuel trims, injector pulse width, engine temp ect.
Something is not adding up, last post on this one.

[Triton2300]

Haven’t had a Suzuki mechanic look at it yet. The Marina I keep it at is just Yamaha mechanics and is closed for the winter as of this weekend for any outside mechanics to look at it. The Yamaha mechanic is going to change the thermostats this winter. I am going to schedule the Suzuki mechanic this spring. Be nice to get a readout on it. Thanks for all the information!