I recently aquired an 83 mercury 18horse for my 1442g3. I really think I need a prop for it. Its got a couple small chunks taken out about the size of a chocolate chip and a hairline crack about 2" long extending from one of them. I assume that warrants replacement. I haven't run this motor on the water yet to see how well it does with this pitch on it. Should I just run it as is and see how it performs or what? I guess I need to put a tach on it and see what the RPMs are but I just dont know if I should bother trying that with this prop or not. But I also don't want to buy a new prop that's the wrong pitch. Anyone got any suggestions?
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When should a prop be replaced?
- Thread starter mogfisher
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ben2go
Well-known member
time to replace
Yeah, I figured as much. Should I just buy a new one thats the same pitch, or try to run this one (as a test) to see if this pitch is OK for this boat/motor combo. Maybe I'll need a different pitch and I'll be bummed if I just replace it with this pitch and it's not right. I'll have to find out what pitch it is and post it up. Maybe some folks on here might have some suggestions if they have similar setups. I'm running a 1442 with 2 batts/troller 2 guys/gear and eventual decking of some sort.
ben2go
Well-known member
The current prop won't give you an accurate idea of its performance.The profile has been changed because of all the damage.You could probably go with a little more pitch on a light weight jon boat.How much,I don't know.It varies motor to motor and boat to boat.
kentuckybassman
Well-known member
Without a doubt!!ben2go said:
Thanks guys. That was kinda my thought on the prop too. Not giving me an accurate representation due to the damage. The local boat shop has one that they recomended for my setup for 120. I'm going to pick it up on Monday. I know I can probably get it cheaper online but I like supporting the small business. These guys are great and have helped me in the past so i don't mind paying a little bit for thier stuff. Any risk invlolved in running this prop just once. I really wanna try it out tomorrow for the first time. No more painfully slow electric only for me.
If it is out of balance, it can tear up bearings and seals. Now, on a small outboard like yours, I doubt it would happen, but on higher hp motors, it is a definite problem. Personally, I wouldn't take the risk, given you will have a new prop in a few days. Also, as bad a condition as it is in, it could fling a blade, and getting back to the ramp on 2 blades is no fun. Again, on a motor of your size, very unlikely, but could happen.
Well, I got the prop changed. Boy was that fun! It was siezed on there good. After much fussing I finally ended up having to cut it off. First I chopped off 2 blades. Then I cut long cuts in the outer ring and snapped off the pieces to get to the middle ring and cut that and do the same. Then once I got that and the rubber off I had to CAREFULLY cut through the splined sleeve and bust that off in chunks too. I was able to get it off without touching the shaft or housing at all with the cut off wheel. After seeing what it was like in there, there was no other way it was going to come off. Run in salt and probably never taken off and greased. I just have one quick question. Behind the prop there is a dust cover and then a splined washer/spacer with 3 legs that line up with 3 notches in what looks like the nut that holds the prop shaft in (maybe). If the spacer were a tad shorter it would interlock into the nut it looks like but as it sits there is no way. It doesn't go in far enough. I was just so excited to get it apart I just yanked everthing off and didn't pay attention to the orientation of this spacer/washer with legs to the funky nut underneath it. Does it matter? And here is a pic of the prop. Look like fun?
ben2go
Well-known member
That's a rough job.You did a good job getting it off without damaging anything else.I have used antisieze on props.I can't help with the other question.
The place your getting your prop from will be able to help you with putting your prop on properly.Buying a prop on line would only cost you about $70 - 80 so the extra and supporting the local I understand & they will too when you ask for their help.
Yeah, I'll have to go ask them I guess. I'm sure they'll know. Question about the anti sieze. The stuff I have has copper in it. does the dissimilar metals thing apply? Isnt the copper what everyone is afraid about with pressure treated and aluminum? i know there is the grey stuff too but I bet that has some sort of metal in it too. Anyway, it's on there and it spins. Cant wait to get it in the water and see how she does.
ben2go
Well-known member
Some has copper some doesn't.The stuff I use is silver and has no copper.Can't remember exactly whats in it but it made by Permatex and I purchased it at NAPA.
Use a white moly lube, available at some parts stores.
For the prop I used some stuff the boat store said to use. I think it's just waterproof grease. If I do it every year and keep up with it I'm sure it will never be this bad. Makes me wanna take the prop of my 06 mercury 50. I havent greased it since new. i suck. I was just wondering about the anti sieze for things like the lower unit bolts and the bolt that holds in the trim tab anode.
