1999 150 Johnson oil usage excessive ?

[Rodster44]

Hi
I bought a used 21 foot Striper WA last year with a 1999 Johnson 150 Ocean pro motor. I used one gallon of oil and 35 gallons of gas in 100 miles.
The motor idles a little rough and smokes more than my friends outboards.
It has lots of power and gets out of the water fast. It runs smooth and strong crusing. Sorry I can's give RPMs as my tach is broken. My top speed
(GPS set on MPH) is 39. My normal cruising speed in 25-27 MPH. I know it is hard to answer but I have no idea how much oil I should use. Is this excessive and if so roughly how much should it use. Thanks
Rod

 

[tx1961whaler]

Re: 1999 150 Johnson oil usage excessive ?

I would say a 35:1 gas to oil ratio is excessive. The good new is it probably isn't hurting anything other than your wallet. The engine will need decarboning sooner.

 

[ezeke]

Re: 1999 150 Johnson oil usage excessive ?

The smoking and high oil use is probably caused by an air leak in the gasoline side of the fuel system. Check the connections and hoses.

With the engine off, put a little pressure on the primer bulb and look for fuel leaking, no matter how small, all the way to the engine. If fuel can get out, air can definitely get in.

 

[Chiliando]

Re: 1999 150 Johnson oil usage excessive ?

Might want to switch to a 50:1 ratio. That is what I use on my 1999 225 Ocean Pro.

Works fiine. Was told by my mechanic not to use more oil than that.

 

[Dhadley]

Re: 1999 150 Johnson oil usage excessive ?

A fuel restriction will also let the oil injection dump more oil. Once you run the vacuume and pressure tests on the pump you'll know for sure. Might be as simple as a sticking anti-siphon valve on the tank outlet. That's the advantage of oil injection. It's saving your powerhead.

 

[Chris1956]

Re: 1999 150 Johnson oil usage excessive ?

Rodster, It is very likely you have an air leak in teh gasoline side of the fuel system. I had exactly the same issue on my '98 Johnny 150HP. I found the main fuel screen under the airbox, was not threaded on properly, causing an airleak. The motor now runs at about 60::1, which is normal. That main fuel screen has a gasket and an oring (I think). If these are bad, you will suck air.

Also check all fittings on the gasoline side of the line. Check the antisiphon valve in the fuel pickup at the fuel tank to see if it is clogged as well as the tank vent.

 

[Rodster44]

Re: 1999 150 Johnson oil usage excessive ?

Hi
Today I changed the water seperator filter. I also looked at the fuel filter under the front cover. That filter looked good and I could blow through it easily. I was going to change it but could not find a boat parts place open today. I will get one Monday. The gas primer bulb did not feel right so I replaced it. It is still smoking but I did not warm it up good or take it out.
It seems to be blowing oil out of the hose that goes to the upper part of the air box. I show a lot of oil in the air box plus oil is laying inside of the intake of the carburators. When it is running and I put my finger over that hose with the motor running and it pulsates. Is it supposed to ?
Thanks to all who are helping
Rod

 

[ezeke]

Re: 1999 150 Johnson oil usage excessive ?

If you are still running two fuel filters, you may be restricting the line too much. The oil tank has its own filter, so the fuel filter redundancy isn't really needed.

 

[Rodster44]

Re: 1999 150 Johnson oil usage excessive ?

HI
I just had a VRO unit put in today. Also correct squeeze bulb and a set of plugs. I will report back when I try it out for a good run.
Rod