85hp evinrude

[dalej]

I have a 85hp evinrude on my boat and recently have a problem with the boat not getting up to speed. The motor sounds great and it runs good but the power is not there now. It goes into both gears forward and reverse just fine but with hardly any power to get up top speed-Thanks,Dale

 

[Nandy]

Re: 85hp evinrude

If the motor sounds as usual (meaning your RPMS are not lost) then you either have a spuned hub or a broken pin in your prop. You can check this in different ways. First, take all of the plugs boots off and ground them. You dont want this motor to start without the water muff or in your hand while you are holding the prop. Put the motor is gear. Take the cover of the motor so you can see the flywheel moving. Now turn the prop, if you turn it the "wrong way" you will hear a clicking similar to what you hear when you are opening a prescription pill bottle. If you turn it the right way there will not be any clicking, it will be hard (depending on how strong you are) and you will see the flywheel moving. If the prop move easily either way or slip when you are moving it the right way you either have a spun prop or a broken pin. With the size of your motor I will guess your props dont use pins.

The other way to try this is to make a mark on the prop nut and the prop, run the motor in the water and then check if the marks are still aligned.

 

[dalej]

Re: 85hp evinrude

HELP nandy !-I tried what you said and the prop doesn't turn freely-do you think the throttle cable is strechted out ? THANKS

 

[tashasdaddy]

Re: 85hp evinrude

the proper way to test a prop is to mark across the hub, then take it for a spin. if the marks are still lined up, it is not the prop. takes a great size man to turn a prop, even if it is spun. the prop is made up of 2 metal hubs, with a rubber bushing, a spun prop, means when torque is applied buy the inner hub, the bushing is slipping, not spinning the outer hub as fast as the inner. thus loss of power, even though, the motor sounds fine.

 

[Nandy]

Re: 85hp evinrude

TD explained how to make the marks in a better way. Try that, put it on the water and check. I dont think is the motor. IF it is still revving like before then it is ok. Do you have access to another prop from friend or something? That will be the definite test. If you have a prop place they might test it for you but I am almost convinced they never test, just replace the hub...

 

[dalej]

Re: 85hp evinrude

I took it out to the water with the prop marked and it is working fine so I am trying to find my next step to narrow it down-any ideas ?

 

[ezeke]

Re: 85hp evinrude

It sounds like you are dropping a cylinder.
Run compression test with all the sparkplugs out.

What is the model number or year of your motor?

Any way you could photograph the splines in your propeller?

 

[Nandy]

Re: 85hp evinrude

If your cylinder compresion looks good and the splines in the prop and prop shaft looks fine I would start suspecting the lower unit. However, we woul be talking about a seriously worn out gear. Check your lower unit lube for metal on it.

 

[dalej]

Re: 85hp evinrude

It is a 1978 85hp evinrude

 

[dalej]

Re: 85hp evinrude

I checked the compression and all looks good at 75 for each cylinder

 

[Nandy]

Re: 85hp evinrude

if they are all about the same it should be ok. 75 is low if you ask me but if they are all the same I would not worry too much. It could be the gauge itself, the important part is that they are the same.