Boat motors: Please, can some one offer some advice from experience? I have a pair of 1999, Yamaha 250HP, 2 stroke motors on my boat. I have an oil pump that is bad. The mechanic...

Fishin' Buddie Loc: South Florida

Please, can some one offer some advice from experience? I have a pair of 1999, Yamaha 250HP, 2 stroke motors on my boat. I have an oil pump that is bad. The mechanic recommended that I convert from the oil injection system to an add oil to the gas system. This sounds like a step back to me. Does any one have any personal experience with that? I don't plan on selling this boat any time soon, so I need to fix it. Thanks in advance for any and all help.

Robert J Samples Loc: Round Rock, Texas

Well, if you don't want to replace the oil pump, I don't see a big problem of adding oil to the gas tank. All the outboard motors back in the late 50's and early 60's, as far as I remember had oil added to the gas tanks. It's little more trouble, but not much. Just Sayin...RJS

flyguy Loc: Lake Onalaska, Sunfish Capitol of the World!

Fishin' Buddie wrote:

Please, can some one offer some advice from experience? I have a pair of 1999, Yamaha 250HP, 2 stroke motors on my boat. I have an oil pump that is bad. The mechanic recommended that I convert from the oil injection system to an add oil to the gas system. This sounds like a step back to me. Does any one have any personal experience with that? I don't plan on selling this boat any time soon, so I need to fix it. Thanks in advance for any and all help.

Welcome to the Forum, Buddie. I had a 115, 2 stroke Johnson that the oil pump went bad, no dings, buzzers, or any warning signals, it just died at 3/4 throttle, it started right up and went 100 yds., died. I checked the oil tank, it had oil, started it back up, went 100 yds. died and it was getting noisy. Called my buddy on the marine radio and he came over and pulled me back to the cabin. We were fishing in Canada and we were 27 miles from the cabin. That is a long pull. My motor mechanic took the pump out and said to add oil, then you know that it is there. He put a new short block in it and I haven't had any trouble with it since. I know a guy that bought a new 2 stroke motor a long time ago when the oil injection started coming out and the first thing he did was to take the oil pump out and then add oil.

sumcatone Loc: Salem VA

I mixed gas and oil most of my boating life and never had a problem. Just pay attention and be sure the mixture is right ratio. Not as convenient and a little messy sometimes but one less expensive part to worry about.

Robert J Samples Loc: Round Rock, Texas

Yes, I agree with sumcatone: Just pay attention. Just Sayin....RJS

ricky risteen

If you pull the oil pump out of the block.Make a cover over the hole in block ,seal it up good with a good sealer that is good with oil.Next mix your gas to a 50:1 mix. 12gals. of gas to 1 qt. tcw3 oil.Also keep a set of fresh sparkplugs aboard.Just in case you foul a plug. The Ricky Sitka

Barnacles Loc: Northern California

The oil pump with a separate oil tank is better - as long as it works. Most oil injection systems vary the oil/fuel ratio depending on how hard/fast the engine is running. That means a savings on oil, plus less plug fouling and carbon buildup. But when the oil pump dies, you're in expensive trouble! Mixing your gas and oil is less convenient and sometimes messy, but it's more reliable - unless you're bad at math and get the ratio wrong.

I'm still using the VRO oil pump on my 90 HP Evinrude, but at the same time I mix oil in my gas at 100:1 so that if the VRO pump fails, I'm still partially protected. Hopefully, I'd get an alarm or realize that the oil tank level isn't changing before damage occurs. That means that I'm spending more on oil and cleaning my plugs more often, but it's worth it for some peace of mind, I think.

Ben Bragg Loc: Dayton Ohio

I recently converted to mix gas on a VRO even rude 70
My opinion is that the VRO was questionable when it was working.
Hate not knowing that something as vital as oil mix in a 2 stroke couldn’t be verified
Swapped to non VRO , mixed my gas and slept better at night
Mixing your own gas takes a little effort but worth it in my opinion

Jeremy Loc: America

Fishin' Buddie wrote:

Please, can some one offer some advice from experience? I have a pair of 1999, Yamaha 250HP, 2 stroke motors on my boat. I have an oil pump that is bad. The mechanic recommended that I convert from the oil injection system to an add oil to the gas system. This sounds like a step back to me. Does any one have any personal experience with that? I don't plan on selling this boat any time soon, so I need to fix it. Thanks in advance for any and all help.

To be honest the oil pump could easily be a fuel and oil pump so may need it to pump fuel on one side of pulse diaphragm. They are very in expensive and very easy to change. You can add oil to fuel but you will be measuring the oil from now on. You will probably have to modify both motors too. I would fix what you have but its your machine.

Barnacles Loc: Northern California

By the way, you can't just put gas in the tank and pour in some oil when you're at the fuel dock. It has to be mixed, or the oil will be a lot thicker at the bottom of the tank until you hit some rough water or trailer the boat at least a few miles. You can mix it 5 gallons at a time and then put it in the tank, but that's a hassle. I got an electric fuel pump from inside the tank of a car at the wrecking yard and installed it inside my boats gas tank. I rigged the pump discharge through a nozzle that causes the gas in the tank to swirl. I switch it on for a few minutes after I put in gas and oil. So far, so good!

jepolt Loc: North East Ohio

Hey Fishin Buddie,

Those 250 Yamahas are great engines. If your fixin to keep the boat, as you stated, my advice would be to get to a certified Yamaha dealer and let them do a complete computer diagnoses of both engines. I am guessing if those engines are 1999 thats 20+ years of use. Guessing you must have somewhere around 800 hours on those guys. See what they say at Yamaha and I suggest you let them get those engines back up to normal. I wouldn't mess around adding oil to the gas or step back in technology to convert to adding oil in with the gas. That's not how those engines were designed. Those 250s have an injection system design that increases and decreases the amount of oil delivered to them on demand based on RPM and speed. Last thing you would want is to be 20 miles out in a lake and have something fail as a result of insufficient oil to the engines. That type engine failure would be a major major repair. Thats my 2 cents based on 40 years of boat ownership. Good luck to you!!

Egghead

I would fix the oil pump. One trip you burn 23.5 gallons fuel up measure your gas according to motor specs next trip out you burn 8.3 gallons mix,add oil repeat over and over. NOW what is gas and oil ratio To rich ? Or to lean? To rich and your killing mosquitos to lean you just killed your motor. Oil pump cheap. New motor expensive. But it's up to you. If you burn it up buty a four stroke. No adding oil.

Able Man Loc: North Coast (Cleveland, Ohio)

jepolt wrote:

Hey Fishin Buddie, br br Those 250 Yamahas are gr... (show quote)

I perceive jepolt's advice, as being very sound advice. At the very least, I'm pretty sure that I'd CONSULT a professional marine engine mechanic, before making any real "modifications".

Jeremy Loc: America

I looked up the Model and application. From what can tell it is not the simple diaphragm type like some outboards use. They are very inexpensive. They have a diaphragm with fuel on one side and oil on other side of it. Then check valves create a flow and pressure. I think yours has a metering system that looks almost like a carb. It has fitting for each cylinder to direct inject the oil. It looks like a 200-500 dollar part instead of the 10-50 dollar diaphragm type.

Able Man Loc: North Coast (Cleveland, Ohio)

Jeremy wrote:

I looked up the Model and application. ... It looks like a 200-500 dollar part instead of the 10-50 dollar diaphragm type.

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