78 OMC 2.5L WaterPump/Oil Pump, Carb Tuning..

[watsbobton]

I have searched around.. haven't found too much to do with these engines..

After replacing a crack manifold I was able to get my 78 2.5 running, but making a noise. I have an OMC 400 outdrive, is it possible to run these out of water? I have the muffs on, all sealed, covering all holes.

-I started to get a whining sound in engine, would this be the water pump, from lack of water?
-Is the OP guage and accurate assesment of the oil pump, or is there another way to check it?
-Rochester 2 Barrel Carb - Should the 2 f/a screws be the same?

Thanks!

 

[southkogs]

I believe you can put muffs on the '78 400 - should be intakes on the sides of the drive.

If you're running the engine on the trailer and the drive isn't FULL DOWN, the ball gears can make a pretty terrifying sound depending on what condition they're in. I wouldn't go much beyond 500 or 700 RPM without having the drive in full down position.

Whining could be a bunch of stuff. Can you tell where in the engine that sound is coming from?

I'm not sure on alternate checks for the oil pump or the correct answer for the F/A screws on the carb. I've never worried about them being the same ... but that might be wrong.

 

[watsbobton]

Okay, I'll keep trying the muffs, and try to isolate the noise.
Just doesn't appear to be pulling any water, which leads me to believe the water pump is making noise.

The ball gears are between outdrive? Is there any maintenance to these?
Also I'm still working on wiring for tilt motor, if drive was down say 90%, would that be okay?

So far from what info I've found, I should be greasing the pivot pins and swivel bearings, plus oil change.
Any other maintenance you can recommend?

I appreciate all the help, THanks!

 

[southkogs]

A Stringer won't "pull" water ... they're designed to be completely submerged and then move water. So the pressure from your hose is what'll get the water into the system. If you've not changed the impeller (bottom of upper gear case), you may just do that for peace of mind. I do mine every couple of years or when I have an overheat issue (happened once). The water pump in the engine is a circulation pump.

I think you can look on eBay for a pivot cap with a hose fitting too (they had 'em for mine, and I thought yours would too). That allows you to put water in over the impeller and feed it up and down. You can also install a flush kit up in the engine and flood it that way.

The ball gears are between the intermediate housing (coming through the transom) and the upper gear case of the stern drive. both the upper gear case and the intermediate housing get gear lube put into them - change annually at least.

90% down might be okay ... but mine still grinds a little until it's all the way down. I don't run it too long on the trailer unless I can lift the stern up and drop the drive way down.

Annual maintenance for me: Oil and filter change, lower gear case lube, upper gear case lube, intermediate lube, grease all points (steering arm, pivot points, swivel bearing). Impeller gets changed every other year.

 

[watsbobton]

No Title

Ok, I have a bit more work to do, so I think I'll try submerging the whole drive.

Yes, I've seen those pivot caps, though mine didn't come with one.

Does the outdrive have to be removed to replace IMPELLER? I found this thread> http://forums.iboats.com/forum/engi...c-stringer-impeller-replacement-pics?t=378358

Is this procedure for the upper and lower? (pic below)

How do I lube the intermediate?

Thanks again for the help, I realize I could find all these answers if I bought a manual, the link in "OMC INFO" is not working anymore unfortunately.

 

[watsbobton]

I have this.. http://www.ebay.com/itm/New-Johnson...367-/360663642579?hash=item53f93a71d3&vxp=mtr
on side of engine near fuel pump.. is this to attach a hose?

Thanks

 

[southkogs]

Does the outdrive have to be removed to replace IMPELLER?

It a heckuva' lot easier to do the change with the drive removed. But you can do it with the drive still on. You'll be working mostly upside down though.

Is this procedure for the upper and lower? (pic below)

Picture you put up was of a Cobra: Fill for your upper gear case should be on the side, and on the older units like mine it vents on the top (remove the screws). On the lower, you have two screws on the side of the drive: upper one is a vent and the bottom is where you drain and fill.

You'll want one of these if you don't already have one: FLUID PUMP

How do I lube the intermediate?

You should have a screw head just outside the transom on the intermediate. Open that up, and you'll need to use a "pump" of some sort to get in there and get it - a turkey baster with a long tube would do the trick. Fill in the same hole.

I have this.. http://www.ebay.com/itm/New-Johnson...367-/360663642579?hash=item53f93a71d3&vxp=mtr
on side of engine near fuel pump.. is this to attach a hose?

I think that's for flushing an outboard. I think you're looking at the oil removal tube; same thing as in this photo near the dipstick?