1989 15 Hp idle issue

[Apexmaster34]

hello, I have a 89 15 hp, with very low run time only about 20 hours. but it has sat for over 20 years, last week i finished doing a complete tare down, on carb, reed valve, spark plugs, new head gasket, etc. it has electric start. engine starts as it should but will not idle by it self. i have set the low idle mixture screw to 1.5 turn out from all the way in.
I am having a hard time linning up the mark on the advance plate with the round thinggy on the top of the throttle arm. one video says they need to line up with about 10% throttle., however mine are so far apart no matter what I do with the idle screw adjuster.

[Joe Reeves]

1-1/2 turns out is the initial setting.... Now adjust it as follows:

(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.

[Apexmaster34]

Thank you for feedback. So I have done this procedure . My concern is the Iinc and sync . I cannot get the carburetor lobe to sign up with timing plate. The guide said with about 10% throttle the lobe should line up w the mark on the timing plate. But I cannot get them to match. I am over half inch apart no matter how much I adjust the screw on the throttle body valve.

[Joe Reeves]

I don't know what you're adjusting (throttle body valve)... BUT... keeping it simple.......... Disregard that 10% mention.

The throttle roller need to be set so that the throttle butterfly just starts to open when the scribe mark on the cam is dead center with the roller.

[Apexmaster34]

Linc and sync said twist throttle a little bit this should line up the timing mark with the carburetor roller. To me little bit is 10%

[Apexmaster34]

its sync and fixed now, however i just noticed another issue, the engine is not circulating water. i have a water pump OEM kit installed, with the pin in correct spot, I have removed my thermostat and test in hot water, and I have cleared all coolant p***ages, and i am still not getting any flow through the motor. I get a little drip, drip but not flowing as it should. at this point I am completely out of ideas. I have taken off Lower and inspected every single component, watched how to videos, and read,.everything matches but I have no flow.

[Joe Reeves]

A$$uming, as you say, that the water pump is installed properly...

It happens that the water tube can at times hit the edge of the grommet in the water pump, and as the lower unit is pushed into place, the grommet will fold over creating an effective shut off valve.

If the above mentioned problems do not exist and all is well as far as your workmanship... the thought occurs that, since the water pump is not a self priming pump... that the water level is not covering and submerging the water pump. The water level must be a couple inches above the water pump location in order for the pump to function.

Where is the water level before you start the engine?

The only other thing that comes to mind is a slightly faulty head gasket... not bad enough to let water in, BUT just enough to allow the combustion power burst outwards into the water pa$$ageway which would cause a stalemate. This would result in the combustion going down the water pa$$ageway... the water coming up... the two meet and just stay in that position... and the engine overheats as a result.

Let us know what you find.

[Apexmaster34]

the water level is 3/4 up the shaft. i have over 5 inches water from the suction hole. i have a brand new head gasket as well,

[Joe Reeves]

Suction Hole!!??.... If you're speaking of the screened area water intake... therein lies your problem. I told you that the pump is not a self priming pump and at that level (5" above the screen) the pump would need to draw the water upwards to it... and that's not going to happen.

The water pump sits on top of the lower unit surface.... the area where the lower unit bolts up to the long exhaust housing.... the water must be 3" or 4" above that area. Hopefully you haven't damaged the water pump impeller.

[Apexmaster34]

i will post picture of water level this morning. i have a 5 gal bucket and it is almost full to rim, and the whole lower unit, and mid part are covered in the water. if its not a self priming pump how do i prime pump, or get it to draw water in it?
thank you for all feedback. hopefully i can get it to start circulating water through the engine.

[Joe Reeves]

As long as the water pump is submerged, obviously full of water... it's primed. The thing is that it must be submerged in order to initially draw and pump water. As the boat increases speed, the engine of course raises up to a higher point BUT at that point of time water is being forced into the water pump pick up areas by the forward motion of the boat/engine.

Being in a test tank, bucket, trash can, or even on a transom but too highly mounted... and the water pump is not submerged, it is drawing only air and that presents a problem.

There may be another problem adding to the overheating situation BUT having the water level initially where it needs to be is the trouble shooting start point.