Prop

[blackcatrain]

Have a 1989 3-cycle 70HP Evinrude outboard which requires another prop due to damage to the existing one. I have in possession a prop with the folowing information stamped on the inter hub where the splines are: #382765 and 13 X 19, I do not know the manfacturer of the prop, could someone tell me if it is compatible with my motor?

 

[walleyehed]

Re: Prop

That is an OMC P/N...but I don't show it as current...If it has 13 splines, it will work as long as you can get 5500+ RPM with it.

 

[blackcatrain]

Re: Prop

Originally posted by walleyehed:<br /> That is an OMC P/N...but I don't show it as current...If it has 13 splines, it will work as long as you can get 5500+ RPM with it.

It has 13 splines and please explain what you mean by "It will work as long as you can get 5500 RPM with it". My 70 Evinrude in a on 8 foot by 32 foot cruiser that I built and the boat never runs faster than 1/3 throttle. I don't know how to relate throttle position and RPM'S Kenny. If I run it on the boat, what perils await me, if any?

 

[davejnz]

Re: Prop

when you open it up to WideOpenThrottle(WOT),your RPM should be around 5500RPM with your current prop.If your current prop wont let your motor turn at its WOT operating range(5500),then your motor is lugging which can cause premature engine failure.Post your WOT RPM's so we can further assist you on which prop will work.

 

[blackcatrain]

Re: Prop

I have no idea what the WOT RPM's are because I never run the boat at full throttle due to its size, 8 " X 32". The boat is run at a very low speed.

 

[joe_morgan]

Re: Prop

You could take it off the boat and run it in a water tank. At least you will be able to assess what the engine will rev to.<br /><br />joe

 

[davejnz]

Re: Prop

You will have to see what the WOT RPM's are with the boat in the water in gear,even if only for a few minutes just to find out.

 

[walleyehed]

Re: Prop

Yes, as davejnz said, it HAS to be run at WOT on the boat, in motion to determine what RPM it is capable of so we can determine where you are for max efficiency.<br />If it only turns 4500RPM for example, we need to get the RPM up to 5700-5800 so the engine is operating at max efficiency at ALL throttle settings.

 

[blackcatrain]

Re: Prop

After talking with a individual who is in the outboard motor business as well as props, I think I understand now what you mean by: The prop will work as long as you can get 5500RPMS from the motor". I have decided not to use the prop and will purchase a re-condition 9 inch prop to go on the motor, he assures me this pitch prop will not lug the motor down and generate a lot of heat. What is your opinon on a 9 inch pitch prop?

 

[blackcatrain]

Re: Prop

Could someone please tell me how to re-connect the heat warning device on a 1989 3-cycle 70HP Evinrude outboard as to where the warning sound will beep? I need information such as wire color, etc!

 

[walleyehed]

Re: Prop

Should be tan, I believe...on the back or top of cylinder head circular object imbedded in the water jacket with a pig-tail usually with knife connectors. The horn is in the control box and if you ground the lead going to the switch box, the horn should sound...