Ox 66 smoking bad

[Antnylsu]

I have twin 1997 225 ox 66 on a 272 grady white sailfish. Recently, both motors started smoking excessively at idle and low rpm to the point where people thank us for keeping the mosquito population down. It looks like it is spewing oil and gas out of the exhaust and into the water. The engines both idle at 700 rpm normally and go up to 5200 rpm. One motor surges from 3600 to 4000 rpms.

The low pressure fuel pumps were rebuilt in january as prevent maintenance and this weekend replaced with a brand new set. It has only seen non ethanol fuel and the main tank is two weeks old. To isolate bad fuel or oil, we switched to the auxiliary fuel tank and drained the oil out of the outboard reservoir and refilled with another brand oil. Other recent attempts were replacing the spark plugs and o2 sensors and checking the oil pump o-ring. All have checked out fine with no change. Also, the oil reservoirs are not leaking down after several days of sitting and are not overfilling.

Does anyone have any other suggestions? Any help is greatly appreciated!

[rodbolt17]

my guess, bad lift pump and or incorrect oil link rod setting.

[Antnylsu]

I will check the link rod tomorrow morning. The lift pumps are running when the key is turned on. Is there anything to check as far as pressure on the pumps?

Thank you for such a quick response. I am trying to get it ready for a florida vacation next weekend. I appreciate all the help i can get.

[rodbolt17]

the lift pumps are pulse operated from a port in the crankcase.
the one you hear running at key on is the high pressure pump.

[Antnylsu]

I misunderstood. Grady white puts lift pumps on the boat to replace the primer bulbs and i thought you were referring to those. The lift pumps bolted to the crankcase were replaced yesterday.

[rodbolt17]

those are primer pumps. and the old walbros are no longer avalible.
smoking at startup is normal.
its due to the fuel evaporates and leaves the oil.
next start up you get smoke.
its almost like a premix two stroke only the fuel and oil are mixed in the VST.

[Antnylsu]

Adjusted the oil pump rod by adjusting till the oil pump linkage had .020 clearance to the stopper. We had to move the rod to the outside hole of the throttle linkage because there was not enough adjustment on the linkage rod when in the inside hole. Even with the new lift pumps, it's still smoking and surging above 1600 rpm.

[Antnylsu]

I got the .020 clearance from the internet but saw in the service book that is supposed to be touching the stopper. I adjusted according to the manual and it's still smoking.

[rodbolt17]

QUIT
STOP your seriously F Ing up.
DO NOT move the rod to another hole.
SIMPLY DO NOT.
do you understand what throttle shutter fully closed means?
lay off the you tubes and the internets.
90% of the information is wrong at best.
with the lower throttle plate FULLY CLOSED, adjust the LINK(threaded part) to obtain .005-.020".
its acceptable,and usually needs it, to remove about 5 threads from the rod.
its is NOT acceptable to randomly change drive holes nor randomly bend the stupid rod.
it changes the arc the rod travels in and can blow a motor.
FULLY CLOSED IS NOT ON THE IDLE STOP SCREW.
I usually disconnect the lower two throttle plates to insure the lower is FULLY CLOSED.
its a TWO STROKE.
guess what Charlie brown.
two strokes smoke.
its worse at initial start but after 10 min or so of cruise speed it should clear up.
about the only two strokes that don't smoke are the optimax,E-tec and Tohatsu TLDI.
the oil and fuel in a standard 2 stroke EFI is mixed in the VST, you may have an excessively rich oil/fuel ratio in the VST that will take a while to burn off.

[Antnylsu]

Thanks, i will move back to the correct hole and cut the threads. I understand that smoke is to be expected but this is a very large amount that does not go away at startup.

[Antnylsu]

Meant after startup. Not at startup.

[Antnylsu]

Moved the rod back to original location and adjusted as suggested. Ran it for about ten minutes with no noticeable change.

[Antnylsu]

Should i look at anything else in the fuel system? Both motors are still surging after new lift pumps.

[rodbolt17]

surging typically indicates a fuel rail pressure problem.

[Antnylsu]

Got a chance to check the fuel pressure this evening. It is holding 34 psi at idle. To be clear with the smoking issue, this is a recent sympton. Previously, the motors would smoke slightly at startup and at low rpm. The motors now have a large amount of smoke any time they are running. They look like they are on fire.