Prop popped into drive when running wide open on neautral switch

[KJonesy93]

While running sea foam through my 99 force tracker 40 hp 2 stroke it shifted into drive. I was doing this in a barral and the prob engaged it chipped the prop repair that the previous owner had done and cut the barral. Did i bust my shift linkage? Or something in the lower unit gears? Now when i spin the prop it clicks in forward but nothing else, regardless of wether im in neutral, reverse, or forward. It seems like it popped right back out of drive immediately. Im hoping there was some sort of safety bearing that would have went before anything else since there must have been a lot of torque with the prop going from dead stop to full speed at an instant. It seems like i finally had her going after weeks of diagnosing and tearing apart (replaced impeller, water manifold gaskets, head gaskets, and now this occurs. I dont want to lose any more time on the water.

 

[Jiggz]

Props are not metal to metal connected to the splined connection or mounting. Instead there is a rubber in-between. And if your case, there is a possibility the prop has spunned out of the rubber or splined connection. You should be able to tell this by manually spinning the prop while in gear and if it rotates freely while the drive shaft is not, then you have a spunned prop.

If the prop spins with the shaft freely, then something else in the lower unit is wrong.

 

[jerryjerry05]

That lower is a Mercury lower and uses their shift mechanism.
If you changed the impeller and moved the shift linkage??
You might have moved the rod and need to re center the linkage??

Drop the lower and move the shift rod back into place.
It could be 180d out.
Experiment while it's off, turn the prop back and forth and turn the rod until you find N.
Then a small turn either way should lock it in F/R
Look on u-tube for videos??

 

[KJonesy93]

This is my first summer working on a boat or engine. I have yet to take off the lower unit and will be doing that today so that I can see if the prop is spun by making sure the drive shaft works in unison with the prop. As far as the shift linkage rod I will have to youtube it to understand what you're telling me as im not familiar with it. I do know that i wasnt having these problems after the impeller change. It was working fine running in the bucket until it slipped into gear while I was reving it at max rpm to burn the seafoam. I was doing this in a trash can, which was probably my mistake. So this is where im at now. When I am in N it allows me to spin the prop with resistance and a clicking, does not allow me to spin backwards. It is the same when im in drive, spins forward with a clicking sound and does not spin backwards. When in reverse it is the opposite and locks when spining the prop forward however, when I spin the prop in reverse it is very resisted and has an even heavier click.

 

[ahicks]

Was this engine on a test stand with no cables hooked up to it? If so, it's possible it just slipped out of neutral. I had that exact same thing happen to a 98 40hp Force I was working on (slipped into gear unexpectedly) just the other day.

I doubt seriously there was anything wrong with the one I was working on. I had the lower unit off doing a pump, and was test running after reassembly. My bet on the one I was working on, and yours, is the linkage wasn't totally engaged in the neutral detent. Kind of like some Ford pickups (and some others) you thought were in park, but end up in reverse!

If the engine was all mounted up with the shift cable and controls hooked up, I would suspect it was something else entirely - like mis adjusted linkage.

 

[KJonesy93]

Was this engine on a test stand with no cables hooked up to it? If so, it's possible it just slipped out of neutral. I had that exact same thing happen to a 98 40hp Force I was working on (slipped into gear unexpectedly) just the other day.

I doubt seriously there was anything wrong with the one I was working on. I had the lower unit off doing a pump, and was test running after reassembly. My bet on the one I was working on, and yours, is the linkage wasn't totally engaged in the neutral detent. Kind of like some Ford pickups (and some others) you thought were in park, but end up in reverse!

If the engine was all mounted up with the shift cable and controls hooked up, I would suspect it was something else entirely - like mis adjusted linkage.

It was on my boat everything hooked up running in a 32 gal can. I unlinked the shift linkage and also pressed the neutral button on the throttle while opening it up a bit. I suspect that either i let off the neutral button or the coupler i unscrewed but left on the upper shift shaft vibrated down and relinked

 

[jerryjerry05]

Take the lower off and turn the shift rod until you find N (no clicking) and then try moving it and see if it connects F/R

 

[KJonesy93]

Take the lower off and turn the shift rod until you find N (no clicking) and then try moving it and see if it connects F/R

Took lower unit off. Im not sure if i was manipulating the shift rod correctly, it didnt seem to turn but just move up and down. Either way, whatever i did i could only get the prop to move in reverse with heavy resistance and a grinding sound in the gear box. I also didnt notice the prop turning with the driveshaft. Also noticed the rubber bulb that you see where the bottom of the shift shaft meets the lower unit had slid up the shaft about 2 inches.

 

[KJonesy93]

Props are not metal to metal connected to the splined connection or mounting. Instead there is a rubber in-between. And if your case, there is a possibility the prop has spunned out of the rubber or splined connection. You should be able to tell this by manually spinning the prop while in gear and if it rotates freely while the drive shaft is not, then you have a spunned prop.

If the prop spins with the shaft freely, then something else in the lower unit is wrong.

Confirmed. The prop spins freely while the driveshaft does not. Spun prop it is. Am i going to need to replace parts in order to fix this or is it as simple as re linking that connection? Ill be hitting youtube to figure this out but if you guys have any more advice or direction it is greatly appreciated. Also might be a good time to just replace my prop unless I want to repair it again. Thanks folks

 

[jerryjerry05]

Most places that deal with boats has a prop repair shop that they send old props to be reconditioned.

You must have a really bad spun hub.
Most time you can't spin the prop by hand even with a bad hub??

 

[KJonesy93]

Most places that deal with boats has a prop repair shop that they send old props to be reconditioned.

You must have a really bad spun hub.
Most time you can't spin the prop by hand even with a bad hub??

I figured it would spin easier if it wasnt linked to the driveshaft?

 

[roscoe]

first mistake, disconnecting the shift linkage. with nothing to hold it in place, it was free to move.

second mistake, taking the engine over 2000 rpm in neutral.
One of the easiest ways to blow up the entire motor.

 

[KJonesy93]

I cannot get my driveshaft to turn at all with the lower unit off. What does this mean?

 

[KJonesy93]

first mistake, disconnecting the shift linkage. with nothing to hold it in place, it was free to move.

second mistake, taking the engine over 2000 rpm in neutral.
One of the easiest ways to blow up the entire motor.

It’s funny how these things are only learned after the fact. I have no background in mechanics and nobody to ask these questions. It’s hard to just know these things. I figured that the engine reving up and down was directly linked to the sea foam burning off the varnish because it would smoke and bog then clear it off and run smooth. Luckily I do know that the engine stayed well cooled that entire time. I would have been worse if I were doing it on muffs I’m sure. But I was checking the water flow and cooling throughout. Aside from the impeller, what other damage do I have to check for? It idled like gold immediately after and cranked right up. One thing I can guarantee is that thing is cleaner than a whistle. As long as chunks of my impeller haven’t broken off into it. The spark plugs were immaculate. I know I messed up, but I’m not gonna beat myself up over it. I bought $1000 boat and trailer setup to have fun with it. I put zero time and money into it last summer other than pure enjoyment and already got my moneys worth. This summer I’m still not giving my money to a boat mechanic. But you can bet your ass I am kicking myself over the fact that I had it running perfect until I got to horny while burning off the last of the carbon buildup and not waiting to get it to the water to complete it. Yes I wish to have it on the water asap but I am learning a ton. Yes I’m glad the engine didn’t blow up and extremely lucky it didn’t thermal lock and take off. Yes I will make sure it’s running fine before I put it in the water. But that will just put a bigger grin on my face when you guys help me get this straightened out and get her in the water for the real fun, as I have a feeling it will be fine.

 

[kbh121956]

KJonesy93. Next time use Mercury's "Powertune" It comes in a spray can with an attached long nozzle meant to spray directly into the carb, It's the best stuff to de-carb an outboard, It'll smoke like a son of a gun while doing it. IMO "Seafoam" is a waste of money. When trying too turn the driveshaft are you turning the shaft clockwise? It's important that you do, If you turned it anti-clockwise, it can mess up the vanes on the water pump. Hoping that your gear case isn't hurt. Try and find a factory service manual on ebay for your motor. You will learn a lot from it. The other manuals are not worth having. Listen to these guys like jerryjerry05 and roscoe and others, they won't steer you wrong.

 

[KJonesy93]

KJonesy93. Next time use Mercury's "Powertune" It comes in a spray can with an attached long nozzle meant to spray directly into the carb, It's the best stuff to de-carb an outboard, It'll smoke like a son of a gun while doing it. IMO "Seafoam" is a waste of money. When trying too turn the driveshaft are you turning the shaft clockwise? It's important that you do, If you turned it anti-clockwise, it can mess up the vanes on the water pump. Hoping that your gear case isn't hurt. Try and find a factory service manual on ebay for your motor. You will learn a lot from it. The other manuals are not worth having. Listen to these guys like jerryjerry05 and roscoe and others, they won't steer you wrong.

Thanks, will give powertune a try next time for sure as its designed specifically for outboard decarb, the seafoam did clean it right up though. As far as turning the driveshaft the wrong way that must be exactly what happened. I forced the prop one click backwards because it felt like it wanted to go and it probably locked up the impeller. I took the housing off and the shaft spins now with the prop. Still think I might have a spun prop as well because it didn't seem like there was that strong of a link between the prop and shaft and at some points they wouldn't spin together. But now after putting it all back together i can certainly tell there is a shift linkage issue. When I have my controller in neutral it acts as it should in forwards and when i put my shifter into reverse my prop acts as its in neutral. I'm all ears. I know what caused my issues,I just want to get to the solutions. Jiggz and jerryjerry05 has been helping me tremendously through the initial diagnosing but one things I'm confused about is the fact that being able to spin the prop by hand is a symptom of a spun hub. Can someone also tell me exactly what my prop is supposed to do while in F,N, reverse? From what I understand N means the prop can spin freely both directions, F means it should spin only forward with clicks, and reverse means it should spin backwards only and with no clicking?

 

[Jiggz]

I cannot get my driveshaft to turn at all with the lower unit off. What does this mean?

Even with the LU dismounted, it's not easy to turn the driveshaft by hand even if it's in neutral because of the impeller. Albeit with little muscle or better yet with a wrench you should be able to turn it just make sure you only turn clockwise looking down on the shaft.

If it's still too hard to turn it thereafter, that means there is something wrong with the gear box. And the only way to find out is to open and inspect. But before doing so make sure you checked everything for the obvious first.