1994 Force 120 HP flywheel rotation

Hi,
I just purchased a 1994 Bayliner Capri 1700LS with the stock 1994 Force 120HP outboard (SN 0E093566). The seller told me that the engine was not running, and his mechanic told him that it needed a new powerhead. I looked at the engine, and it seems to be very clean! Actually, overall, the boat is in immaculate condition, and I have all the paperwork including the original brochure, manuals, etc.

I am new to outboards, but have rebuilt small British engines way back when, so I am pretty mechanically inclined. I first want to manually turn the flywheel to see if the engine is locked up. But, I have read that some outboards have CW rotation, and I couldn't find any information on the '94 Force. I looked at some videos online and it seems to be that the flywheel rotates CW. From reading some online forums, I guess that I can do some damage to the water pump if I turn in the wrong direction. If I can turn the flywheel, then I will proceed to compression testing.

Does the '94 Force 120 flywheel rotate CW or CCW?

TIA,
Chandran

It rotates CW

It doesn't matter which way you turn it.
Remove the plugs and hit the solenoid to jump it. Check the plugs for water or metal??
If you remove the plugs and use the key to turn over you need to ground the plugs or possibly fry the pack.
If it doesn't turn over ?? drop the lower unit. Then try to turn it over. The bearings on the driveshaft can seize and lock it up.

If you get it to turn? then do a compression test. You'll need to have all the plugs out for that.

Post the results????

Oh yea WELCOME!!!

Jerryjerry05 said:

It doesn't matter which way you turn it.
Remove the plugs and hit the solenoid to jump it. Check the plugs for water or metal??
If you remove the plugs and use the key to turn over you need to ground the plugs or possibly fry the pack.
If it doesn't turn over ?? drop the lower unit. Then try to turn it over. The bearings on the driveshaft can seize and lock it up.

If you get it to turn? then do a compression test. You'll need to have all the plugs out for that.

Post the results????

Oh yea WELCOME!!!

Click to expand...

Thanks, Jerry, Alice.

I can rotate the flywheel by hand CW; I read that if I rotate the wrong direction I could damage the impeller. I just got a remote starter so that I don't have to use the ignition key. I will be checking the plugs and if it turns over soon after all this rain has passed. I'll post my results.

You won't damage the impeller.
Unless it's so old the vanes break off.
If you just bought it? I'd change it anyway(after it's fixed).

We had a semi-dry Saturday so I had a chance to work on the motor. Compression for pistons 1-4 was 125, 135, 135, 135 psi. Hooked up the muffs and cranked the engine. 1 st try engine turned over and died after about 15 sec. 2nd try engine dies after about 30 sec. 3rd try engine ran, kinda rough. I saw smoke come out of the exhaust but no water (from the two holes right below engine cover). Put the motor in forward, and saw the prop spin. Then after about 3 mins I heard a high pitched sound coming from the dash, so I shut off the engine.

I was pretty sure the water is not circulating around the engine. I waited about an hour for everything to cool down, then started it up again to check the water pressure gauge...zero. Again, no water coming out of the two engine ports. Turned off the engine after about 15 secs.

Any ideas on how to proceed? Is it a simple change of the impeller? Shouldn't I see water coming out of the two ports with the water running and the engine off? I am concerned that the water cooling path is obstructed, but not sure how to check. I noticed the small male port on the top of the engine near the flywheel that has a tube connected to the pressure gauge. I was wondering if I can run water through there backwards to see if it comes out of the two exhaust ports.

TIA!

You need to change the impeller.

When using a flusher or muffs you need a LOT of water from the hose.
Or a real deep bucket. The water needs to be over the cavitation plate by 3-4in.

If you have a pressure gauge then it should show something if waters being pumped.

It's a good thing the overheat buzzer worked or you could do some damage.

IF???? your even a bit mechanical you can change the impeller.
While your at it, change the gear oil.
The drain is on the bottom of the case.
(see pic)There is a slotted screw on the side of the case, don't remove.
It's the linkage anchor pin and will be a lot of work to fix.

The 2 holes on the back, water might or might not come out there??
That's more of a pressure relief port.

Most exhaust comes from the snout on the bottom.

I am still waiting for my service manual to arrive. In the meantime, I want to make sure that the water pump case is not damaged before I buy a rebuild kit. Here is a picture of my engine.
Are the linkage anchor pin and oil drain screws correct?
Do I need to drain the oil before I remove the lower unit?
To remove the lower unit, I remove the 6 bolts, plus the one in the snout. Do I need to remove the shift linkage (?) shown in the picture? It is held in place by a cotter pin.
Do I keep the engine in neutral, forward or reverse before I remove the lower unit?

Thanks for your help. I just can't find enough info online for my Mercury Mariner 1994 Force 120, hence I have ordered the service manual.

No they are opposite.
Yes remove the linkage.
Makes no difference on shifter location.
But I usually leave it in F.
That way. If I need to rotate the shaft for installation it's in gear.
It's easier to drain the lower while it's still on.

Try U-tube for repair videos.

The factory manual will have a lot of good info.

Should be this, correct?

That's the one.

I emptied the gear box and the oil looked black and used, but no signs of water. The water pump case looks good, but the impeller is definitely worn out.

When I inspected the lower unit, I noticed a worn rubber part that has left small powder-like shavings around. I tried to identify this part using the engine schematics, but the drawings seem to imply that it is not a removable piece, and the case is continuous in that area. Below are some pictures, with the rubber part circled in red.

Can anyone identify the part, and what is its purpose? TIA.

I believe it keeps the exhaust going in the right direction.

Black oil is good.
Make sure you change the gaskets on the fill /vent screws.
The bottom drain should have a gasket too.
Change it also.

If it's an allen headed screw make sure you use sealing tape.
Pics of the screw/gasket? You could have the older style?

We had some decent weather these last days so I got back to work on the motor. All parts and the service manual arrived. The water pump looked fine, just replaced the impeller, gaskets, water tube and some exhaust seals, shown below.


But when I was inspecting the lower unit, I found an exhaust tube seal (square) down in the lower unit. The exhaust tube seal (25-F439736) comes from the driveshaft housing. I don't know how it got sucked down to the lower unit exhaust area.


I hooked up a water hose directly to the cooling tube on the engine (with no lower unit) and got the engine to run without any heating issues, at least for 10 mins before I shut the engine off. The water pressure was abut 7-8 PSI, and I could feel warm water coming out of the ports.

So how do I go about replacing the exhaust tube seal? The shop manual did not discuss this procedure. I have a bad feeling that I need to remove the powerhead...

TIA!

Yup that's how it goes in.
If it didn't affect the way it ran before???
Probably not. I wouldn't worry about it.

Does the exhaust come up into the cowl? Probably not.

It's there to ensure the exhaust goes out through the lower unit.
Without it, the exhaust can escape from the front and around the other parts of the drive.

OK, you just made my Memorial Day weekend! I was almost certain that the seal was a vital part of the engine and if it wasn't there then water would fill up the cowl. If I were to fix this seal, can I get to it by removing the motor leg (aka drive shaft housing aka exhaust housing)?
My Force service manual doesn't discuss this part of the engine, and I only see glimpses of the exhaust tube in a few figures.

So, there is one thing I forgot to mention about the impeller, and that's the direction of the vanes. I placed the impeller over the key and slid the pump housing cover over the drive shaft. The impeller was pushed into the stainless steel cup by rotating the drive shaft clockwise.
Is this the correct direction?
The Service Manual has a picture of an impeller inside the stainless steel cup, and the direction of the vanes is opposite of how I installed it.

Have a great holiday weekend!

Makes no difference .
The vanes will orient themselves.

Had a blast fishing in Oriental, NC over Memorial Day weekend, and got me excited about getting my boat in the water!

So, I put the lower unit back together, removed the prop and used a 100 gal water trough to test the engine. I also replaced the thermostat.
View attachment 13523

Started up fine, and was able to stay in neutral for a few mins before shutting down. Engine temp was warm, not hot like previously, so I am fairly sure cooling problems are solved. So I started the engine up again, put the engine in forward, and also reverse without any problems. 1200-1400 RPMs in idle, and I had it up to 3200-3400 RPM in forward. The engine was running OK for a good 15-20 mins, again no heating problems. Water pressure was about 3 PSI in idle. I noticed a good deal of black exhaust, but thought that was just from the engine being in fired up for the first time this season. After opening the throttle for awhile, the idle seemed smoother, but still skipped a beat every now and then.

Now the bad news. I turned off the engine, waited about an hour, then tried to start it up again, but it wouldn't run. The engine turns over fine. Recharged the battery just to make sure, then tried again the next day with no luck. So, I pulled the plugs and #1 and #2 was black, while #3 and #4 seemed pretty much how they looked when I first started this project. I cleaned the plugs and below are the before and after pictures.
View attachment 13524

When I crank the engine, it sounds strong, but seems like either no sparks, or no fuel. I ordered gaskets for the two carbs, since I haven't checked them out yet.

Any suggestions on how to proceed or what to look for?

Cylinder drop test,spark test,look for big blue snapping spark

The first thing i'd suggest is start another thread.
New problem, new thread.
Maybe as a Mod to move it?


Both attachments don't open.

Outboardignitiondotcom has test procedures.
Sounds like the stator might be bad?
You'll need an analog meter for basic tests and a DVA adaptor for the more complicated.

Doesn't sound like the carbs.

Do a compression and a spark test.

Check the flywheel key.

Post the results.