Guess im done 4 summer

[Mudflap]

1975 115 Merc, I give up! I've tried 3 differant props, I'ts always the same,I launch my 16 ft ski boat,It comes out of the hole just fine for a trip or two around the lake and thats it, party's over, she starts slippen so bad I cant get her up on plane! just like spun prop, oh well this money pit has just about tapped me out, probably tarp the old girl till my other ship comes in. REGUARDS MUDFLAP

 

[Specks n Reds]

Re: Guess im done 4 summer

 

[Mudflap]

Re: Guess im done 4 summer

No, I'm not sure of anything But why would loosing a cyl. cause the motor to tach out and prop wont keep up,oh ya, motor's been maried to boat since 1975.

 

[Fouled Plug]

Re: Guess im done 4 summer

Are these 3 used props? Try painting a line from shaft to hub, and try a couple holeshots. If the lines no longer match up, the hub is toast. 3 bum props? Unlikely, but possible.

 

[Mudflap]

Re: Guess im done 4 summer

It did it with prop that came with boat, so prop doc center punched hub and prop, marks lined up even after couple hole shots, then I tryed a used prop,same sinario, then finnally out of desperation we put a brand new [out of the box]prop on it and no change. I'm totally befumbled and missing some hair that used to grow on top of my melon, any input is totally appreciated

 

[NathanY]

Re: Guess im done 4 summer

Sounds like it is ventilating, is the trim all the way down? Is the pin in the lowest setting? Have you tried a hydrofoil?

 

[ob]

Re: Guess im done 4 summer

Or you got some stripped driveshaft splines or a gear clearance problem in the lower unit.

 

[Mudflap]

Re: Guess im done 4 summer

Yes Nathan,I have pin in lowest hole and I have tried it with and without whale tale, I'm starting to think the only answer is to take to shop, but I've spent so much resurecting the darn thing it's not an option at this time many thanks!

 

[JB]

Re: Guess im done 4 summer

Hi, Mudflap.<br /><br />Is your anti-ventilation plate (sometimes called the "cavitation" plate) level with the bottom or keel of your boat?<br /><br />The more posts I read, the more your problem sounds like prop ventilation.

 

[SeaMasterZ@aol.com]

Re: Guess im done 4 summer

try draining your lower unit oil, see if its gritty or metallic looking, if so shes eatin her gears down below, if not top her off make sure shes squared away with the bottom, take a board and place it on the bottom of the boat, see if the board lines up with the cav plate<br /><br />if all that checks out, I dunno ... put her up on plane and hold her back to just enough throttle to keep her on plane, cruising - if she can do that, use her til its button down for the season time and then try to figger it out<br /><br />Good Luck!

 

[iRich]

Re: Guess im done 4 summer

If it works fine for the first couple of trips around the lake each time, I would rule out the prop and ventilation plate. If either were the culprit I don't see how it could go good for a couple of runs and then not. Maybe it gets hot ? I would check compression and start thinking engine problem instead of the prop. I know the prop would be an easy fix but if it isn't that you have to look elsewhere.<br /><br />Rich

 

[Hooty]

Re: Guess im done 4 summer

Don't suppose the boat is taking on water and getting real heavy do ya?<br /><br />c/6<br /><br />Hooty

 

[MajBach]

Re: Guess im done 4 summer

When you say it's good for a trip or two around the lake, do you mean same day? If the prop works for more than one trip then gives it's a big difference than if you have a few minutes of good boating before you lose power on the same outing. If it is the latter, your engine is obviously losing power. Do the rpm's stay up and the boat just doesn't move? If that is the case ( for certain ) than it does sound like the props are giving out on ya. Sure you have your thrust washer on?<br />I cant see any other way of having full rpm range but no power.<br />If you are noticing and rpm drop from the start of a trip to the end, then you could indeed have engine probs. I had an evinrude that did this and it turned out to be the needle valve sticking. Taking on water is also a real possibility.<br />Maybe need to be more descriptive.

 

[Hooty]

Re: Guess im done 4 summer

Bump

 

[onebohemian]

Re: Guess im done 4 summer

Same kind of thing was happening to my buddy's 84 alumacraft with 90 horse merc. Would get up on plane first time in the water, but after a couple of times of moving to new fishing spots would start to rev out. He had recently put a new prop on. Turned out that when he replaced the prop, he took the old washer/bushing from the old prop and placed it between the nut and prop housing like the old prop was mounted. Even though he tightened the sh*t out of that nut, the washer/bushing wasn't meant for the new prop's housing and under load would heat up and then allow the prop to spin loose on the shaft. When you'd stop the boat, the prop seemed tight on the shaft, but under motor load, she'd spin out. Took us a while to figure it out and we were sure it was something more serious until a mechanic explained that he shouldn't have moved the washer/bushing from the old prop to the new prop. Hopefully you'll find out it's something as simple.<br /><br />Mark<br />Minneapolis, MN