1969 Crestliner Aluminum w/omc 140hp issues with getting on a plane..

[mr.andy]

Hello all,

My boat has a omc 140hp engine paired with a 120 sterndrive.

I got the boat on the water and it seems the boat does not want to get on a plane so when i throttle it kind of just revs the engine a bunch but I dont get anymore speed out of it... I was told its possible my prop might be spun or my outdrive is not deep enough? I look to see if i can lower my engine a bit to get the outdrive lower but I could maybe adjust how its sitting to maybe get it lowered by an inch.

Next time i am out on the water I will update with photos of the back of the boat in water.

So before i was told that I bought some self adjusting trim tabs for the back of the boat and installed them, they definitely helped with stability and such but still not getting on a plane.

I took the propeller off today. And it seems there is no spindle nut on there so it cant really be spun right? The shaft does not seem to have any play. The shaft spins because of the breakaway pin, but looking in the manual it seems the backend is missing a thrust washer there was not one to be found. So i ordered one and will put it on shortly.

Now my question is, can a missing thrust washer cause my boat not to get on plane and accelerate properly?


thanks,

Andy

 

[Scott Danforth]

Wrong prop for the drive

 

[mr.andy]

Okay, how do i know whats the right one?

Thanks,

Andy

 

[southkogs]

Welcome aboard Andy:

Is this a new-to-you boat, or is this a problem you're now having with a boat you've run well in the past? Have you changed the impeller and seen the splines on the drive shaft?

 

[kenny nunez]

The propeller in the picture is the correct style for the drive. To check if the rubber hub in the prop is slipping mark the outer edge of the prop where the pin is located and try the boat out . If the mark has moved the the prop needs to be repaired or replaced. For your combination I am guessing that your boat needs a 14”x14” or a 14”x16” pitch in aluminum. The pitch is imprinted on the prop.

 

[mr.andy]

Welcome aboard Andy:

Is this a new-to-you boat, or is this a problem you're now having with a boat you've run well in the past? Have you changed the impeller and seen the splines on the drive shaft?

This boat is new to me, I have been working on it throughout the winter it has not been taken on the water since 1995. Replaced engine because it was seized and outdrive too.
I am assuming the splines are behind the prop? Take those flat head screws out and it should be there?

I have examined the impeller to the water pump and it seems to be in fairly good condition so I did not replace it.

I will check the prop numbers when I get home, can I possibly run the test with a hose or does it need to be completely submerged in water?

thanks,

Andy

 

[southkogs]

The stringers are prone to a problem with the shaft coming out from the water pump going down into the lower gear case. There are splines on the top and the bottom (male and female respectively). That shaft tends to get stripped out at times.

Kenny's right on the prop I believe. That style can spin, so you'll want to check that according to his instructions. I guess let's also make sure you've got good ball gears up top and then the dreaded water log question: are you sure the hull is dry and in good shape?

 

[southkogs]

... or does it need to be completely submerged in water?

In the water. You need the propulsion forces on the screw.

 

[mr.andy]

Okay not trying to sound like an idiot , but want to make sure so behind that cover that's being held by those flat head screws is where i can examine the splines and look for that shaft if it has indeed fallen out? As far as the hull goes it is dry and in good condition no weird bowing or anything I am having a very slight leaking issue from the seal on the back I believe but no other problems, and am working on fixing that too.



Edit: So this is the entire shaft with the splines I need to examine correct? Wouldn't i feel play in the shaft if it were to be worn out?

https://www.ebay.com/itm/Omc-Cobra-S...wAAOSwQItUEa-F

 

[southkogs]

If you're leaking through the transom boot, you need to check for some water issues. I'm not saying that's an issue, I'm just saying to make sure you check. Looking and feeling the surface of the stringers and the deck are not telling you the story. Make sure you're checking the wood within - maybe drill a sample in an inconspicuous spot - and see if there's trapped moisture. Right now, that doesn't sound like your main problem but it may be a contributor.

The shaft you're showing in your link is for a Cobra. You've got a Stringer. (Or that's what you should have based on year) The shaft that is the more common culprit in the Stringer is #35 below (in the red box).


If you were to physically grab it while installed, you may feel some play if it's bad but perhaps not. If you've got enough hand strength and you've got the upper gear case detached from the boat, you can possibly turn the entire upper by hand using that shaft.

From the prop, you shouldn't be able to tell anything. The Stringer prop spins free until it's engaged in gear. The upper gear case is always turning if the engine is running, and the low only turns when the coils are energized.

In my opinion visual inspection is your best route on that shaft.

Again, it's a common thing - not a guaranteed problem. Check the prop hub too.

 

[mr.andy]

Okay thank you for the information I will do the spun prop test first then i will keep going forward with the other diagnosing.


As far as the boot goes it seems to be leaking from the bottom of the seal I believe the hose clamp needs to be replaced and the fact that the boot seems to be warped a bit towards the bottom so the lip is curling up a bit when trying to clamp so its causing a not so good seal on the lip of the bottom of the intermediate housing.
The boat is aluminum so the only wood that would be absorbing water would be the transom ,the transom however is brand new and is sealed with lots of layers of marine epoxy so I am not to to worried about trapped moisture.

thanks everyone for the feedback so far will keep you updated as soon as i get more information!

 

[kenny nunez]

The boot can be replaced without removing the drive, some liquid soap will help. It should have been replaced when the transom was repaired. If you turn on the ignition and shift it into forward you will not be able to turn the prop shaft in 1 direction then just the opposit in reverse.

 

[kenny nunez]

Also do not remove the 4 screws and the gear case head. You cannot get to the forward gear that way unless the exhaust housing is removed and the swivel bearing is off and the shift wires out of the way. Since the boat does move in forward tells me that the forward shift is in good order. Does the lower unit have the correct fluid. If it has 90 wt. gear oil that may be the problem. Automatic transmission fluid is a good substitute.

 

[mr.andy]

Okay sorry everyone for the late update been very busy, So what I have discovered my prop was fine it did not move after marking it, I got to thinking and realized the outdrive on there came from a different boat and was a different size than the original that came with the boat, It happened to be a 4 inches longer.
So i swapped them out I was reluctant to use it because it has been sitting and untested from the outside storage facility for looong time. Anyway I hooked it up to the hose and everything seemed to be functioning like it should so i got the boat ready and drove up to the lake and sure enough I went on a plane! I was able to hit 32mph which is a pretty solid speed in my book.

Now recently I am starting to have issues with the engine but i believe it to be carb related (fingers crossed), its like its having a misfire but not a complete misfire its very strange and the carb seems to be spitting fuel through the top of it now. It is still running and turning on fine but there is definite power loss, I bought a carb rebuild kit and hoping to rebuild entire thing and see how it is then.


Thanks for feedback so far guys!

Andy

 

[southkogs]

Shaft length on the drive that you put on was longer? If so, then just the shaft length could have been the issue. If the drive you just put on is the shorter, then likely that the other one may have a different gear ratio going.

Either way - glad you're up and going.