Major Power loss

[ngentile]

Today:

Had a great day out on Lake Jesup - Orlando FL. (Caught 16 speckled pearch before the cold front moved in).

Have a 1987 25hp Mariner. On the way out, every time I would attempt WOT it would sound like the prop was out of the water spinning and experienced major loss of power (which was not the case, I never had cavitation problems). Every time this happened throttled down a bit and we were fine. So I kept it just under WOT the rest of the day. On the way back we ran into some sand in the shallows, no problem tilted the motor got off the sandbar and cruised just under WOT all the way back until about 200 yards from the ramp the power died and couldn't get the boat above trolling or idle speed. The pressure and combustion all seems to be fine. It starts, rev's up and idles fine. Luckily this happend on the way back very close to the ramp.

What could this problem be? It's got to be some kind of pin or maybe a gear that's come loose... not sure never had this problem.

Any help would be appreciated. Thanks all!

 

[Silvertip]

Re: Major Power loss

You need a rebuilt prop or a new prop. The rubber hub that separates the hub of the prop from the blade area has broken its bond so under full power or near full power, the load on the prop overcomes the existing bond and things slip. Any propeller repair shop can fix this or a new prop is not a major expense either. Check the prop for numbers that identify the diameter and pitch or the manufacturers part number.

 

[ngentile]

Re: Major Power loss

Sure enough.. took off my prop, put a random tool in my vice that fit tighly in the teeth on the prop and you can see the hub moving when I started to move the prop. I worked it back in forth until a bunch of chewed up rubber substance started falling out. Finally the hub came out. I did some research and found that a company rubex makes a special "do it yourself" hub kit. When you tighten the hub the rubber piece expands and tighens up. Guess the days of prop shop are no longer necessary. They market that rubber is better than the traditional plastic because it's more shock absorbant.

Thanks again. You were absolutely right about this problem.