Lots of noise, but no forward progress

[johnglen]

I have a 1990 Evinrude VRO 90 HP (model E90TLESB). When I am cruising slowly and push the throttle forward there is a lot of engine noise and much churning of the water but there is very little forward progress. The bow is out of the water and it's as if the boat is furiously treading water. Backing off and slowly increasing the throttle will occasionally work and I can attain full speed.
My knowledge of outboards is similar to my expertise in quantum physics (none). I read about "dogs" and "pinion gears" and wonder if this is where my problems lie. Before taking it to the local marina I'd like to have some idea of what the mechanic will be looking for and if my problem sounds like an expensive fix.
Thanks to all who can help me.

 

[Daviet]

Re: Lots of noise, but no forward progress

Can you define engine noise? Does it knock or bang, does it seem to rev up , but does not provide any power?

 

[Miroash]

Re: Lots of noise, but no forward progress

Did you check to see if you spun the prop? If you have a spare prop, install it and see if it corrects the problem.

 

[noworries79]

Re: Lots of noise, but no forward progress

Not trying to steal the thread, but can you define spun prop? I am having a similar situation. Thank you

 

[Miroash]

Re: Lots of noise, but no forward progress

Not trying to steal the thread, but can you define spun prop? I am having a similar situation. Thank you

It is when the propeller does not turn as fast as the shaft it is mounted on. The propeller is slipping on the hub. similar to a stripped nut on a bolt. so you can rev the motor and maybe get a little forward motion but not very much. One way I have seen people check for it is to turn the prop with the motor in gear, if it slips, then you have a spun prop. BE SURE TO REMOVE THE KEY AND LANYARD TO AVOID HAVING THE MOTOR START WHEN YOU TURN THE PROP.

 

[johnglen]

Re: Lots of noise, but no forward progress

It is when the propeller does not turn as fast as the shaft it is mounted on. The propeller is slipping on the hub. similar to a stripped nut on a bolt. so you can rev the motor and maybe get a little forward motion but not very much. One way I have seen people check for it is to turn the prop with the motor in gear, if it slips, then you have a spun prop. BE SURE TO REMOVE THE KEY AND LANYARD TO AVOID HAVING THE MOTOR START WHEN YOU TURN THE PROP.[/QUOTE

Do I understood you correctly when you say to place the motor in gear with the engine off and attempt to turn the prop? I did this and the prop freely turns, but I thought that all props did this. If this is indeed the problem do you know what the fix is? Thanks.

 

[johnglen]

Re: Lots of noise, but no forward progress

Can you define engine noise? Does it knock or bang, does it seem to rev up , but does not provide any power?

Just the usual noise of an engine under load. In other words it revs up fine, but there is little forward progress.

 

[Miroash]

Re: Lots of noise, but no forward progress

If you have the motor in gear it should spin free in one direction but not the other. in one direction it should be turning the motor (which is why you want to be sure it will not start)if not then you most likely have spun the prop. take the prop off, and take it to prop shop they can repair the hub, or purchase a replacement prop whether it be a new or used one. look at your prop there should be some type of markings on it telling you pitch and diameter.

 

[johnglen]

Re: Lots of noise, but no forward progress

It is when the propeller does not turn as fast as the shaft it is mounted on. The propeller is slipping on the hub. similar to a stripped nut on a bolt. so you can rev the motor and maybe get a little forward motion but not very much. One way I have seen people check for it is to turn the prop with the motor in gear, if it slips, then you have a spun prop. BE SURE TO REMOVE THE KEY AND LANYARD TO AVOID HAVING THE MOTOR START WHEN YOU TURN THE PROP.[/QUOTE

I misled you on this as I noticed after I posted that I had not fully engaged the shifter. When placed in the full forward position I can turn the prop about 2" forward and reverse before it stops. Does this seem to indicate a spun prop or is it normal action?

 

[imported_Jimbo]

Re: Lots of noise, but no forward progress

Sometimes it is still possible to turn the engine even if the prop is spun, but the tourque of the engine will be strong enough to rotate the inner hub of the prop while the outer is moving slower (rubber in between them), hence the sound and slow acceleration. Try another prop, to me it surely sounds like the prop is your problem!

Let us hear how it goes!

BR Jimbo

 

[Miroash]

Re: Lots of noise, but no forward progress

Sometimes it is still possible to turn the engine even if the prop is spun, but the tourque of the engine will be strong enough to rotate the inner hub of the prop while the outer is moving slower (rubber in between them), hence the sound and slow acceleration. Try another prop, to me it surely sounds like the prop is your problem!

Let us hear how it goes!

BR Jimbo

Agreed, I think the best and easiest thing to do would be borrow a prop from someone (I would not worry about it being the correct pitch, it is not important for test purposes) and install it and see how the boat acts (if the pitch is different it could change the hole shot or top speed performance) but it should work enough to tell you if in fact it is the problem. also, if your prop is bad enough you might get your answer when you remove your current prop.

 

[johnglen]

Re: Lots of noise, but no forward progress

Agreed, I think the best and easiest thing to do would be borrow a prop from someone (I would not worry about it being the correct pitch, it is not important for test purposes) and install it and see how the boat acts (if the pitch is different it could change the hole shot or top speed performance) but it should work enough to tell you if in fact it is the problem. also, if your prop is bad enough you might get your answer when you remove your current prop.

Before I get into switching props, I want to make it clear that this is not a consistent problem. On a trip last week the motor performed fine; it was on another trip a couple of days ago that the on/off problem arose. This has been happening for two seasons now. If it was a prop problem wouldn't it be a perpetual issue, rather than on/off? I inspected the prop, which appears to be in near-new condition. Thanks again.

 

[Miroash]

Re: Lots of noise, but no forward progress

Before I get into switching props, I want to make it clear that this is not a consistent problem. On a trip last week the motor performed fine; it was on another trip a couple of days ago that the on/off problem arose. This has been happening for two seasons now. If it was a prop problem wouldn't it be a perpetual issue, rather than on/off? I inspected the prop, which appears to be in near-new condition. Thanks again.

I had a prop that was spun and only gave a problem every now and then. but it only got worse over time and eventualy failed completly. It is possible you do have another problem, but from what you are describing it sounds like the prop. but with the cost of a prop you will want to be sure before you purchase another, but it doesnt hurt to have a spare.

 

[imported_Jimbo]

Re: Lots of noise, but no forward progress

Agree, a spun prop usually shows itself during high load, but will get worse and worse. Try another before you dig into the lower part of your engine...

 

[OptsyEagle]

Re: Lots of noise, but no forward progress

The better test for a spun prop is to put a scribe mark above and below where the rubber hub is, so the scribe marks line up. Take the boat out for a spin and when you return, see if the scribes still line up. If they don't, then the prop is spun.

Since you can almost always get a trolling speed out of a spun prop, I doubt turning the prop by hand, while in gear, is a suitable test unless your arms can put out the same torque as 90 horses.

 

[Miroash]

Re: Lots of noise, but no forward progress

there is a lot of engine noise and much churning of the water but there is very little forward progress.

The above mention comment in the origonal post made me think the prop was bad enough to spin by hand, which is why I suggested it. but yes a mark on the prop will tell you for fact if the prop is the problem, or you could switch props, whichever is best option for you. I think most people have a spare prop to switch it, which is why I suggested it.