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Evinrude cavitation going straight

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Georgiaboy67

Advanced Contributor
I have a 97 evinrude 115. E115eleua. My boat loves to cavitate. I noticed that I have a slight lean to the right when I sit down. All my stuff is to the left of me to balance the weight, but it's still leaning. Could this be the cause? I was told the anode on the lower unit could also be the culprit. It's always wobbling, and I tried to seal it on which eased some of the wobbling, but now when I hit a certain speed and trim the motor vibrates loud, at first I thought it was gonna blow. Any ideas? Would a jack plate at like academy or Walmart help reduce this? Or would I just have to keep adding weight to balance it.
 
It's right hand rotation, and the motor has been on the same spot for 20 years. Just started recently. Boat load also lightened up, it was my uncles boat, he had a lot more gear then I did, and he was heavier, but it never cavitated unless we turned sharp and fast. Now going straight it cavitated. But it wasn't like this last week.
 
Could the sacrificial anode stone that I have on the back of the lower unit cause this? I've read somewhere they can be weight distributors. Could this also just be from the old spark plug wires? A guy jammed a circuit tester needle in th boots and that's when it initially started. But now it's gotten worse.
 
you stated that this problem had problems before.....when you turned left or right. your prop needs to be lowered. i had a similar problem when we could not find a extra long shaft motor. we solved this by using a electric jack plate. we installed the motor at the correct depth with the jack plate in the lowered position. problem was solved and the motor could be raised for shallow water and for transport home.
the sacrificial anode will not cause cavitation.
 
Yikes I wish had the money for an electric jack plate. And that makes sense! But how come it does this going straight? It has NEVER done that before.. Weight hasn't changed, as in where things are sitting on the boat to distribute evenly. But the last two weeks it got to the point that even with it trimmed down all the way it sounded like it got air..
 
lets talk about the cavitation problem...can we assume you hear the motor rev when it happens and its really a cavitation problem?...if so the problem was always on the boat..then you got it and lightened the load and it got worse...where is the cavitation plate in relationship to the keel or bottom of the boat?..it should be even with the bottom...

the vibration is another problem...its just my opinion but I think you always had a cavitation or whatever problem and now the 2nd problem has developed and you are trying to relate the two...I would check compression on the engine and the spark with a spark gap test on all cylinders as a starting point..you said you knew the vibration problem started with inserting a meter lead into a spark plug boot...after doing the compression and spark test and those two look ok I would use an inductive timing light on all cylinders to make sure fire was there at the time of failure..
 
I see at least two problems working on this rig with related problems...some facts in each of them that should be all in one to get best results..for starters has the engine been recently rebuilt?
 
It's a remanufactured Powerhead. It was running fine for a while. But I've narrowed it down to the bushing on the shift lever is gone. For the rattling at least. I feel it in the throttle, and it goes away after I hit plane. I'm going to try to test prop this weekend. I think this cavitation that I thought was the issue is the hub on the prop is spun. When it doesn't do the cavitation thing It hits its maximum speed. The rattling noise is not effecting it's speed. Not for now anyways. Yes I've always had a cavitation issue. But not going straight. It only did it when I turned fast and sharp. Rpms jump up, speed goes down. And does it with the motor trimmed down all the way.
 
And yes that mimics cavitation. But when it really cavitates the rpms jump up more then what it's doing now. A spun prop hub came to light yesterday. It's the original so yeah my guess it's that.
 
I failed to mention prop in my first entry on the problem...that's what was on my mind when I asked if it was really a cavitation problem...sorry about that...
 
The anode is not going to cause it. Do you have a tranducer located near center line of boat? Is the prop is good shape as your new powerhead is putting out max hp/ torque than your old worn motor.
 
I can't get pictures to post on here. I created a social media account to post pics, let me take a pic and post it. The prop is worn out if I had to guess the real issue, it's consistently gotten worse, and the prop is the original one�� Trying to get the money for a new one. Not sure exactly where to mark the hub on the prop to see if it's slipping or not.
 
Scratch or use a felt marker straight across the prop and the inner hub if it is steadily getting worse it is probably the hub is slipping. If you have a prop shop close they may be able to press in a new bushing but buying a new prop is usually more cost effective.
 
Well did the mark that kimcrwbr suggested, hub isn't spun. Took the anode off just to see and ran perfect.. What sucks more is I can't leave it off or I can kiss my lu goodbye
 
Yep. The old one's bolt head was broken off years ago, so finally I got tired of hearing it move around since it came loose. I drilled the old one out and put a new one in and it continued to do the same thing. Although the new one was in kinda crooked. But because I can only self thread it it was a pain in my a** to get it tightened up all the way.i couldn't hold it straight and tighten it at the same time cause it took a lot of Stength just to tighten it
 
Houston we have a problem, just noticed that I don't have a thrust washer at all on this prop.. It's never had it since I got it from my uncle. Could this be why the problem keeps getting worse?
 
Scratch that. Thanks to the people that helped on another forum of mine, I do have a thrust washer, found an old thread on how to pop it off. came right off just like they said, the hub that's between the prop itself and the gear case has circular marks on it, along with the thrust washer, definitely spun.
 
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