4 stroke using oil?

[Northlander]

I have a Yamaha 115 4 stroke. My ? is how often should I have to be checking oil and possibly adding some?

What do those of you with these motors do?

Also what size props are you running? Stainless size as well as Alum sizes please. What RPM's do you turn with each different prop? Thanks a lot for info.

[Northlander]

Someone must have some info for me. TTT.

[MRWALLEYE2005]

Stainless steel is definately better for performance and durability. Just looking at the cabelas site it looks like the stainless steel 3 blade costs about 3 times more than aluminum.

[CFRay]

I have a F115 on a Lund ProSport. No oil use that I can notice. Change it each year before winter storage. Recently put on a Turning Point Hustler, Alum., 2005 model, 13 1/4 x 19. I do like the way it moves me out of the hole better than the Yamaha prop that came with the unit. 4800 rpm gives 38 mph. Plenty for me.

[Hemlock]

Hey Northlander, not sure if you want my input on my Honda 130, but I'll give it to you anyway

I've got a 19 pitch aluminum prop that gets me 5100 RPM (lower than I would like, but the 17 pitch doesn't change it much) It's on a 21' Sylvan bowrider. I get 46 mph (GPS and speedometer) and it doesn't burn a milliliter (ounce ) of oil. Change it once a year with 200 hours on it a season.

Going to give the stainless a try this weekend. Marina dude is letting me try it to see if it's worth the $$ He says rarely do people return them.

[CHODE]

Hey northlander, I run a yamaha 2-stroke Hpdi, and I was told by a buddy who sells and services boats that Yamaha motors perform best with Yamaha stainless props, well after trying numerous brands of props, I tried a yamaha stainless 14-1/2 X 21 and I must say the performance is unbelivable! If you can afford to try one I would say go for it.

I ended up in the correct rpm range and picked up alot of speed.

He also said mercury runs pretty good on the yamahas, but I tried one and it was a far off second choice.

[Northlander]

Im running a 13 by 19 yamaha Stainless and push 5400 rpm and 42 mph. Thats the best prop I have found so far. Hustler 13 by 19 dropped rpm's to 5000 and 49 mph. I have a 13 by 17 that Im getting tweaked and Ill see what that does when Jay Soderbloom gets threw doing his magic on it.

My 115 yamaha 4 stroke seems to be using some oil. Not much but I had to add 1/2 quart last week. Its ok now but I wonder why I lost that oil. I had just recently changed out the oil and filter. Could it all have just settled after the oil change?

[BIG DS]

The best prop for your motor should keep the RPM's right at 5400 to 5600. Keep in mind, the stailess props are more durable, a little better in the performance area, but also can severly damage you gear case if you were to hit a rock. The aluminum will mess up the blades pretty bad and you might have to replace the prop, but that would still be cheaper than rebuilding the lower unit. Stainless don't tend to give and something else inevitably will and it's usually something expensive like a prop shaft. If you have a prop that keeps you at about 5200-5400, have the hub drilled on the leading edge of the blade by someone qualified and that should give you optimum preformance. A factory Yammy prop 13x19 should be about right.

How old is the motor and is it broke in? If you see no leaks above the cavitaion plate, it should use next to no oil.

[BIG DS]

After changing oil and filter on any 4 stroke yammy, start the motor let it idle for a minute or two with water, either in the lake or with ear muffs, shut it off and let it sit for about 5 and then check the oil. You will need to add some every time unless you overfilled it in the first place.

[Northlander]

Big D I think thats all that it was. The only seems to be staying at a good level the past few times out. I was hoping it was just the oil settling after the oil change.

Its a 2003 and yes was broken in when I bought it.

Where exactly would you drill that hole you talked of?

Thats what Im having done to that 13 by 17 stainless.

[Northlander]

TTT

[marine_man]

Quote:

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The best prop for your motor should keep the RPM's right at 5400 to 5600.

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What's the reasoning on this? The upper limit of the RPM range as specified by Yamaha is 6000.. why run it 8% below the top rated RPM?

I'm not questioning your reasons.. just trying to understand them. I've always heard you're best off at the upper end of the RPM band to keep from lugging the motor...

marine_man

[ChuckN]

I agree with Marine Man. 115 Yammy 4 stroke is recommended in the 6,000 RPM range.

Aluminum props are not fail safe either. My aluminum prop lightly hit a chunk of underwater concrete at a launch at idle, and bye bye lower unit gears. You hit anything, you risk damage...regardless of prop.

Stainless are the way to go. I would keep the RPM's in the upper bracket of 5600-6000 RPM's for best performance. I noticed the manufacturer says 5000-6000 RPM range, which is a broad range. A 17 and 19 SS pitch is fairly common.

For losing oil that's strange. I've always read of owners who have that motor "make oil".

[Northlander]

Chuckn I heard the same thing. Mine seems ok now after I added that little bit about a week after the oil change.

Im running about 46 RPm full throttle and getting about 42 mph. Im thinking I should be able to get a few more MPH. I dont know Ill see what that new prop design Jay comes up with does. Thanks guys.

[marine_man]

Quote:

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Im running about 46 RPm full throttle and getting about 42 mph

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Northlander - so... does that mean 4600 RPM? That's really low.. and you're really lugging the engine at wide open throttle... I would get that 17 pitch prop on there quick... but something doesn't sound quite right there... only 4600 RPM with a 19 pitch prop? It sounds like there mut be a lot of cupping on the prop to pull you down that far...

Refresh my memory... what are you running for a boat again? If I recall it' an 1800 explorer.. but I'm not sure...

marine_man

[Northlander]

Im sorry I meant 5600 RPM.

Ya I have a 17' Explorer SS with a 115 Yamaha 4 stroke. I push between 5400 and 5600 RPM and alone in the boat with livewells filled, full gas and gear I get about 40 mph. Half gas and empty livewells I get about 43 mph.

My holeshot is great but I think I should be able to get more top end.

[Fishing Junky]

Northlander, have you played with the motor hieght at all? You should gain another 100-200 rpm's per hole and gain holeshot and a little top end. I had a 16ft Lund tyee with a 115 yamaha 2-stroke and ran I believe a lazer II on it. I think it was a 20 pitch. Boat ran 50 mph's. I raised the motor two notches on it and it really helped. Smaller boat than yours of coarse. Good luck, Junky..

[Xplorer]

Steve,

I would think that you could get a few more mph also. My 90 runs WOT at 39.1gps with full tank and gear and me, and thats at 5600rpm. I think our hulls are similar in weight (mines about 1100#). And, I'm only running a stock 17p aluminum prop.

Hey Junky, did you get any blowout in turns after raising your motor two holes?? I have been thinking about raising mine 1 hole and seeing how the performance is. I'm no racer, but think that i may get a little better performance just by raising one spot, vs the cost of picking up a stainless prop (plus i spend a good amount of time on Namakan/Kab/Rainy, which is full of prop eating rocks!).

Thanks for any info. Did you raise it yourself and how difficult was it if ya did?

[marine_man]

Thanks for the clarification Northlander... I'm not so sure about getting more speed though.. to get you up to the 6,000 RPM you'd need to drop prop pitch, which would get you better hole shot, but you would also loose some speed... unless you switched to Stainless, which should, in theory, get you the best of both worlds.. good hole shot and increased speed... although I think you'll need to go to a 17 to get there on RPM...

marine_man

[Northlander]

The prop Im running now is stainless. The one I have Jay Soderbloom tweaking is also stainless. I dont want to bring the motor up a notch because Im already getting blow out on turns and having to trim down at times. Maybe I should just be happy with what I have?

[Fishing Junky]

Xplorer. When I first bought the engine (used) it had a stainless prop on it. I think 17 pitch. I assume it was a stock Yamaha prop. With the motor sitting on the transom, it would blow out on me surprisingling easy. I went and bought a Lazer II or Phazer II, (can't remember the exact name as it has been about 8 years), made by Mercury. If I remember correctly, it came in even pitches, and I went with a 20 pitch. Put the prop on and no blow out whatsoever. I raised the motor two holes and really noticed the improved perfermance. Out of the hole and top end. Increased rpm's also. All BS aside. I could go wot trimmed up and take the wheel and crank back and forth with no blow out at all. Wow, great prop. At wot, I reveved 200 rpm's over redline. Perfect. Boat loaded it got me to the top end of my rpm range. Although, it was a 16ft boat and you boys have a little more boat in front of the engine than I had. I also wieghed 130 lbs. (good ol' days). So your applications are different of coarse. Wieght distribution is going to play a role in blowouts also. Too much weight forward on a console is not good. As far as raising the motor up, I did it MYSELF. No help. Although I recomend a second person. First, I dropped the trailer in the front as far down as it would go using the tongue jack. I cribbed from the floor up underneath the motor mount. I trimmed the motor down as far as I could and cribbed under the skeg, just to keep the motor vertical. Took out top bolts and loosened bottom. Had to pry motor away from boat to unstick the silicone between the engine and transom. Went to front of boat and started cranking trailer up untill the holes lined up. Put top bolts in loosely and put wedge between transom and motor to create room to re-silicone. Tighten up and your done. All I can say is the whole setup worked awesome on this boat. I would strongly recomend that Merc prop to anyone. Hope this helps, Junky.....