Mercury 9.8M

[SalmonAddict]

So I upgraded from my 5hp to this 9.8hp mercury.
I bought the motor off a friend and he was able to show me the neutral, forward and reverses were all working.
I get home one day, start it up, warm it up. Try to put it into forward and reverse myself and the engine makes a loud thud and dies off. It's so weird cause it was just working!!!! Grrrr I'm having bad luck. Oh and my garbage bin that's was used when I turned on the motor, the water was so cloudy and smelly.

I leave the motor off and try to turn the lever from neutral to forward, back, then to reverse. To forwards it's an easy click. But to reverse its super hard and won't let me push lever back.

Also there's these black oily and grease stains on the ground where I hang the motor from. But unsure if there is any relation.


HELP PLEASE!!! Don't want to go thru another motor!

[AlexanderS]

I'm defiantly not a professional,but I did buy broken outboards and fix them up. My most recent was an early 90's 8hp Nissan-seemed to work fine started up after sitting for a while.took it out on the lake and worked fine for about 30 min then every time I put it into gear it would dye. So first thing I did was buy new gas(mine is a 2 stroke so I made sure mixture was correct) and it didn't seem to help much.eventually I ordered a new file pump and lines which aren't expensive and easy to replace,cleaned out the carb and after that had no issues. And it is REALLY important to change your gear oil! It can also cause this problem where the gear oil is too dirty and thick after not being replaced and can eventually become a very expensive fix! I live in the mill creek area and I have an extra bottle of synthetic gear oil and I have the pump that's needed to change it,I can help you change it for free,as long as you pay for the oil or buy your own(a lot cheaper then paying $120 minimum to have it changed at a marine store:)

[Larry3215]

There are many many possible reasons for why the motor dies when you put it in gear. Did you let it warm up enough? Did you have the muffs on and water to the lower unit?

Like Alexander said - what condition is the fuel and lines and filter in? What kind of fuel was put in it last? How old is it? Did they use any fuel treatment? Was it non-ethanol or regular gas? How old is the plug and what is the gap and what condition is it in? Did you do a compression test or a spark gap test?

You didnt say what year that motor is so I dont know if it has points or electronic ignition - did you do any tests or checks on that? Have you played with the needle adjustments or linkages on the carb?

A good shop manual will be necessary to go through all the possibilities on the above items.

As far as the shifter not wanting to turn, thats probably a linkage issue or it could just be gummed up or corroded or it could be an issue in the lower end - hope its not the lower end = $$$. You will also need a good shop manual to check and adjust that.

Do you know where the oil/grease is coming from? There are several possibilities and some are much much worse $$$ than others. You need to clean the motor thoroughly and then run it again and see exactly where the leaks are. Once again you will need a good shop manual to tell you what to do once you know where the stuff is coming from.

If you are not mechanically inclined, this could be a very difficult job. You are never going to get the detailed advice and instructions you need for anything beyond the very simplest solutions to the simplest problems.

Good luck!

[SalmonAddict]

What don't make sense is that when my friend showed the neutral/forward/reverse, they were all working and just 2 days later when I try it, it don't work.

I'm defiantly not a professional,but I did buy broken outboards and fix them up. My most recent was an early 90's 8hp Nissan-seemed to work fine started up after sitting for a while.took it out on the lake and worked fine for about 30 min then every time I put it into gear it would dye. So first thing I did was buy new gas(mine is a 2 stroke so I made sure mixture was correct) and it didn't seem to help much.eventually I ordered a new file pump and lines which aren't expensive and easy to replace,cleaned out the carb and after that had no issues. And it is REALLY important to change your gear oil! It can also cause this problem where the gear oil is too dirty and thick after not being replaced and can eventually become a very expensive fix! I live in the mill creek area and I have an extra bottle of synthetic gear oil and I have the pump that's needed to change it,I can help you change it for free,as long as you pay for the oil or buy your own(a lot cheaper then paying $120 minimum to have it changed at a marine store:)

The carburetor was cleaned and fuel lines/filter are all good. I also been told that the lower unit oil was just changed in March. Thanks, until I know the definite problem, ill let you know if I may need your help.

There are many many possible reasons for why the motor dies when you put it in gear. Did you let it warm up enough? Did you have the muffs on and water to the lower unit?

Like Alexander said - what condition is the fuel and lines and filter in? What kind of fuel was put in it last? How old is it? Did they use any fuel treatment? Was it non-ethanol or regular gas? How old is the plug and what is the gap and what condition is it in? Did you do a compression test or a spark gap test?

You didnt say what year that motor is so I dont know if it has points or electronic ignition - did you do any tests or checks on that? Have you played with the needle adjustments or linkages on the carb?

A good shop manual will be necessary to go through all the possibilities on the above items.

As far as the shifter not wanting to turn, thats probably a linkage issue or it could just be gummed up or corroded or it could be an issue in the lower end - hope its not the lower end = $$$. You will also need a good shop manual to check and adjust that.

Do you know where the oil/grease is coming from? There are several possibilities and some are much much worse $$$ than others. You need to clean the motor thoroughly and then run it again and see exactly where the leaks are. Once again you will need a good shop manual to tell you what to do once you know where the stuff is coming from.

If you are not mechanically inclined, this could be a very difficult job. You are never going to get the detailed advice and instructions you need for anything beyond the very simplest solutions to the simplest problems.

Good luck!

I let it warm up but not sure of what "enough" would be. I let it warm up for 5 minutes, is that enough?
I don't have any muffs, I just stick the lower unit into water in garbage bin. is there something wrong with this method?

Like stated above, fuel lines and filter are good.
I asked my friend and the fuel that's left in the tank he gave me is from September....maybe this is a start?
No kind of fuel treatment and regular gas with oil (50:1) was used.

Spark plugs showed good spark, were replaced last February. They looked good, can anyone tell me how big the gap is suppose to be? oh and Ill look into compression later today.

Its a 1980

No I haven't played with the needle adjustments on the carb either. With you stating that, I can say that if I put the motor into shift and don't push the lever into forward/reverse, the motor does die on me too. Could just a needle/linkage adjustment on the carb do it?

Oh boy, hope it don't get bigger than that. $$$ is not what I have to throw around...

[hewesfisher]

NEVER shift an outboard motor into gear, forward or reverse, if the motor is not running. There is a dog clutch to connect the drive gear to the driven gear and if the motor is not running (or the prop spinning) and the teeth aren't lined up perfectly, it won't go into gear. Attempting to force it can damage shift linkages and/or internal shift components. Remove the spark plug wires from the plugs and spin the prop while attempting to shift into reverse. If it does not shift easily, STOP and seek skilled help. Based on your other comments, that might be the wisest thing you do.

[SalmonAddict]

NEVER shift an outboard motor into gear, forward or reverse, if the motor is not running. There is a dog clutch to connect the drive gear to the driven gear and if the motor is not running (or the prop spinning) and the teeth aren't lined up perfectly, it won't go into gear. Attempting to force it can damage shift linkages and/or internal shift components. Remove the spark plug wires from the plugs and spin the prop while attempting to shift into reverse. If it does not shift easily, STOP and seek skilled help. Based on your other comments, that might be the wisest thing you do.

Oh man, I'm a newbie for real. I will not do that again.
So your saying I can only shift with motor off if I turn the prop?
Where is this dog clutch? And would it be easy to align it back up?

Oh and there is a link rod on the outside of the driveshaft assembly. It moves in and out. Does this stop the motor going into reverse? (Numbers 18,19,20,21,22 on attached diagram)

[scraig1962]

My 73 7.5 mercury had one of those rods. It keeps the motor from tilting up when its put in reverse and in the water.

[hewesfisher]

NEVER shift an outboard motor into gear, forward or reverse, if the motor is not running. There is a dog clutch to connect the drive gear to the driven gear and if the motor is not running (or the prop spinning) and the teeth aren't lined up perfectly, it won't go into gear. Attempting to force it can damage shift linkages and/or internal shift components. Remove the spark plug wires from the plugs and spin the prop while attempting to shift into reverse. If it does not shift easily, STOP and seek skilled help. Based on your other comments, that might be the wisest thing you do.

Oh man, I'm a newbie for real. I will not do that again.
So your saying I can only shift with motor off if I turn the prop? YES
Where is this dog clutch? And would it be easy to align it back up? It is inside the lower unit. When you shift into F or R the appropriate gears connect. The dog clutch is not like one in a car, they are a set of gears similar to the ones in this pic, notice the square cut teeth...



Oh and there is a link rod on the outside of the driveshaft assembly. It moves in and out. Does this stop the motor going into reverse? (Numbers 18,19,20,21,22 on attached diagram)

That is your shift linkage and if not properly adjust can prevent shifting into either F or R and can also cause severe damage to the lower unit and/or gears. This is why I suggested you find skilled assistance before you cause irreparable damage.

[scraig1962]

Even though your buddy said the lower unit oil was just changed, I would check and make sure its full. Also, if its like my 73, you dont put ear muffs on the lower unit. There is a water intake hole on the lower unit. You gotta make sure its completely under water and that theres water peeing out of the tell tale tube right away when you start it. When I used to flush my motor there was always oily black stuff in the water bucket. I was told it was just unburnt fuel/oil coming from the exhaust.

[ebpip]

NEVER shift an outboard motor into gear, forward or reverse, if the motor is not running. There is a dog clutch to connect the drive gear to the driven gear and if the motor is not running (or the prop spinning) and the teeth aren't lined up perfectly, it won't go into gear. Attempting to force it can damage shift linkages and/or internal shift components. Remove the spark plug wires from the plugs and spin the prop while attempting to shift into reverse. If it does not shift easily, STOP and seek skilled help. Based on your other comments, that might be the wisest thing you do.

I'm not trying to troll, legitimate question here, as i had never heard this. My question is since a lot of outboards have neutral start protection (engine must be in neutral to start), what happens if the motor dies while in forward or reverse? you have to shift to neutral to start. Seems that there must be some protection built in to accommodate the occasional need to shift while not running. Anyone know?

[Larry3215]

The key part of that statement is dont force it. Shifting when the motor is off is normally fine as long as you keep that in mind - at least on all the old ones I ever worked on.

In fact, there are many times Ive been working on various outboards and the manual tells you that you are required to shift it into or out of gear to do linkage adjustments or in working on the lower unit.

If its off and wont go into or out of gear, you may need to turn the prop or crank shaft slightly. If it still wont shift, you need to drag out the shop manual and find out why. Be sure the plugs are out or disconnected before turning the prop or crank shaft.

Be double sure you know which plugs to unscrew to check/drain the lower unit oil. Some motors have more than one screw in the same area and taking the wrong one out can undo critical parts in the lower unit requiring special tools and full disassembly to correct. Been there done that!

[hewesfisher]

I'm not trying to troll, legitimate question here, as i had never heard this. My question is since a lot of outboards have neutral start protection (engine must be in neutral to start), what happens if the motor dies while in forward or reverse? you have to shift to neutral to start. Seems that there must be some protection built in to accommodate the occasional need to shift while not running. Anyone know?

Look at the square cut gear picture again. When IN gear those square cut teeth are meshed, when out of gear they may or may not be. If the engine dies IN gear, F or R, placing the shifter in neutral does not create the condition described when out of gear with the engine off or not turning the prop.

Simple example you can see and do. Take both hands, curl your fingers, and match finger tip to finger tip with both hands. Push real hard and tell me if you can "mesh" them into one another. No. Now rotate one hand or the other so your finger tips point to the web of your knuckles, push your hands together. Did they mesh easily? Yes. Do they separate easily? Yes. That's what happens when a running engine dies and you put the shifter into neutral.

[SalmonAddict]

Problem solved. I should get a knckle to the head for this.

I called a specialist to just help me run basic home check to see if it's anything major.

He told me to make sure there is clearance for the prop at the bottom so nothing contacts it.
So there I am putting the motor into the barrel and sure enough it was contacting the bottom.

So I added 1.5ft to the stand and start it up. Boom it works properly.

Thanks y'all!

[SalmonAddict]

Now gotta get the mercury 40 gnat running...

[Hunter757]

Good for you....always the easy things that hurt the worst. Glad you got it going.