spun prop or what

Having problems all at once. Almost impossible to get boat on plane. 1989 Evinrude 40 hp on 17 foot aluminum boat. Wide open it slowing builds up rpms and after a long tme and slowly trimming up it will get on plane. I have read on here that it could be s spun prop. Does that make sense and how can I check to be sure. #e40tecec. After finally gettting on plane I can acheive max rpm and also the boast is not overloaded. Also I have an extra prop I could try but it the boat is 50 miles away. Does any body know the size of the prop nut so I could take the correct size socket. Thanks.

Re: spun prop or what

That's not how a spun prop.hub would act.

A spun prop/hub would have the engine running at a very high rpm when at full throttle with the boat moving very slow if it moved at all...... AND there is no way that it would ever get up on a plane.

Check the bottom of the boat (if it's kept in the water) for marine life. Check the false bottom of the boat for water (rain water will get in there).

Engine.... Check compression and spark. If these two areas are okay, it's possible that the engine has carburetor problems. Also check the timer base under the flywheel to make sure that it is not sticking.

Re: spun prop or what

Is this a new problem, or has it always done this, or if the boat is new to you, do you even know?

Re: spun prop or what

this is a new problem it has been fine all summer. it's like when you open it up out of the hole it just builds up rpm's slowly and would never get on plane without trimming. once on plane I can obtain full max rpm's

Re: spun prop or what

Oh yes it CAN be the start of a hub slipping. As I have said, it happened to me. Nuff said.

Totally different setup with boat/motor of course. However, my hub problem was found due to taking my prop in to get repitched and the worn hub was found and replaced at that time. The prop shop explained it to me. So, slipping hub does not necessarily mean that the hub is spinning freely from the prop, just slipping enough to not get the full torque needed to plane out.

Do follow the engine advice first though as that is usually where the problems lies. If all else fails, take a permanent marker and mark the prop nut/shaft and on the prop with a line, then run it on the lake. If the marks do not line up afterwards, your hub is slipping.

Re: spun prop or what

tHANKS i WILL check but also the second part of my ? was what size socket to remoe prop nut as is 50 miles from my home

Re: spun prop or what

frozenokie said:

Oh yes it CAN be the start of a hub slipping. As I have said, it happened to me. Nuff said.

Totally different setup with boat/motor of course. However, my hub problem was found due to taking my prop in to get repitched and the worn hub was found and replaced at that time. The prop shop explained it to me. So, slipping hub does not necessarily mean that the hub is spinning freely from the prop, just slipping enough to not get the full torque needed to plane out.

Do follow the engine advice first though as that is usually where the problems lies. If all else fails, take a permanent marker and mark the prop nut/shaft and on the prop with a line, then run it on the lake. If the marks do not line up afterwards, your hub is slipping.

Click to expand...

A spun prop results in the RPMs increasing but without gaining speed, that's not what's taking place here.

Re: spun prop or what

bobjoe1 said:

tHANKS i WILL check but also the second part of my ? was what size socket to remoe prop nut as is 50 miles from my home

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those nuts are not on tight, just bring an adjustable wrench or channel-locks and you'll be fine!

Re: spun prop or what

ondarvr said:

A spun prop results in the RPMs increasing but without gaining speed, that's not what's taking place here.

Click to expand...

The motor will slowly get up to about 3000rpms, mind you slowly not reving quickly and if I slowly trim I can obtain plane and then I can actually acheive max rpm

Re: spun prop or what

Check compression and spark on all cylinders. Let us know what you find.