2020 Yamaha F250 prop on 226

[Lite Tackle]

Got out yesterday to try to get through the 8 hour break in on new motor. At idle, I could barely hear the motor running. Ran motor just in gear for one hour. Gave me a chance to tune electronics, with the exception of the radar which I forgot to land the battery at the RI10 interface box. Very happy with the Airmar B75H Chirp transducer and the Lowrance HDS12 MFD. The HDS8 in the radio box networks perfect with the main unit. The Lowrance Point One GPS antenna was well worth the investment.

Back to motor. After the very slow hour, I was able to run at varying speeds for short durations. I could run on plan with both tanks full (new tank = no issues) at about 20mph. If I recall, 25mph was right at 3500rpm. Finally later in the day got to wot. Reached 46mph at 5600. Wondering about prop. I kept prop from OX66 2225 (15 3/4X 17 SS). Thinking about going with the SDS 15 3/4X15 for two reasons. One, vibration and clunk when shifting into gear and two, to get RPM closer to 6k rpm. Anybody, have a similar boat with an optimum prop?

Just a note, my scuppers are just at the waterline with both tanks full. I am thinking my motor might be mounted to low and may raise it one hole.

Thoughts appreciated on any of the above.

 

[DennisG01]

Just a note, my scuppers are just at the waterline with both tanks full. I am thinking my motor might be mounted to low and may raise it one hole.

The height of your motor won't affect your scuppers in any way. But it could be affecting your top end speed/RPM. Before you try a new prop, be sure that the engine is at the right height when on plane... take a look at the anti-ventilation plate - ideally, it should be skimming across the surface of the water. If it's buried, it's too low. Once you know that, then look to make other changes. If the height is good, then going down 2" in pitch like you are thinking, is just about right.

 

[Lite Tackle]

The height of your motor won't affect your scuppers in any way. But it could be affecting your top end speed/RPM. Before you try a new prop, be sure that the engine is at the right height when on plane... take a look at the anti-ventilation plate - ideally, it should be skimming across the surface of the water. If it's buried, it's too low. Once you know that, then look to make other changes. If the height is good, then going down 2" in pitch like you are thinking, is just about right.

Thanks for the response. I realize the scuppers and engine height are not related (although engines weight are). I was just rambling in my post. Lots to think about after my first real shake down run. Looking for real world experience from a Grady brother with similar configuration. I’ll take the GoPro next trip and mount it to watch the a-v plate. At rest it appears too low.

 

[DennisG01]

Thanks for the response. I realize the scuppers and engine height are not related (although engines weight are). I was just rambling in my post.

Ah, gotcha... two separate thoughts. Carry on!

 

[Lite Tackle]

I do appreciate your input Dennis. Seems two of the biggest worries of the Grady owner are scuppers under water and engine height to low. Especially for newer power on older hulls. Just looking for confirmation that in the words of the immortal Bob Marley, “everything’s gonna to be all right”.

 

[Doc Stressor]

I run a 16" prop on my 226 with my new Honda 250. It turns 5900 rpm at WOT, but only after raising the engine 1" to get the anti-ventilation plate above the water.

Here is a tip about your engine break-in: Yamahas have a long history of making oil. That's actually the oil getting diluted by raw gasoline. It's the reason that I got rid of my F250 after 9 years of changing or draining some of the oil every 30-hr. The reason for this problem is not fully understood. But the most common associations are too gentle a break-in and running over propped.

Get your engine hight right and then prop the engine to get at least close to 6000 rpm at WOT. The shop manual (from Japan) tells you to run the engine at WOT for 6 one minute intervals during the second hour of the break-in period followed by 9 minutes at lower speeds for cool down. This is not what the US owners manual says. Interestingly, when Mercury sold 4-stroke outboards made by Yamaha their break-in procedure was the same as the service manual and you rarely hear of those Mercs making oil.

The idea is to operate the engine under load once it has fully come up to operating temperature. This can be accomplished by running the boat off plane at 2-3000 rpm or by giving bursts of full throttle. It's best to do both during break-in. Load produces high cylinder pressure which seems to be necessary to properly seat the rings under the low operating temperatures required to run outboards in saltwater.

 

[leeccoll]

No useful advice on my end, but CONGRATS on a spankin new engine!!
Guess Santa doesn't come up the hill

1-I raised my scuppers 3" a few summers ago. However, they were both underwater. You are good there.

2-When I changed out the 17 degree pitch saltwater prop that came with my boat for a high altitude one (14 degree pitch Mercury Enertia 3 blade) purchased from Ken @ Prop Gods, I raised the engine up one slot on the bracket. The anti-ventilation plate now seems like it's right at the water's surface when I am on plane (as Dennis previously suggested). Engine is using the top slot now FYI. My engine bracket is very old, I would assume yours is not the older Springfield bracket.

3-What Doc said about seating the rings during break-in is important for a long (mostly) trouble-free engine.

Congrats again my friend!

 

[wrxhoon]

I have a hardtop 228 G with a 4.2 lt 250 Yamaha as fitted at Grady factory.
I spin a 15 3/4X 17 SS , again as per factory fit.
This boat only comes with one tank (125 gal) fitted forward right up the cab door with the 10 gal water tank right behind it.
Fishing with full tank, gear and 3 on board I get 5900-5950 rpm at WOT on calm water and trimmed out . Not sure if 226 is easier or harder to push throughout the water ( the 228 has more flotation and 2012 models more than earlier as well) . Check on G/W website the difference between the 2 hulls.

 

[Parthery]

From the looks of your trim gauge you could probably trim it up a little more too.

Something else I noticed - that's an old school two stroke tach. Even with flipping the dip switches, I'm not sure you won't get warnings like low oil pressure, etc... You might want to consider upgrading to the newer Yamaha tach designed for 4 strokes.

 

[Lite Tackle]

Thanks all that responded. I need some more time behind the wheel before I consider any potential changes.
1. Check height of anti-cavitation plate on plane.
2. Trim motor out fully when checking for max RPM’s
3. Reconsider Yamaha USA motor break-in (hour two was spent varying between off plane load and WOT).
4. Tach compatibility was confirmed and is it designed for both 2-stroke and 4-stroke motors and all warning indicators as well as other functions work correctly for the new motor (per Yamaha Factory Authorized Technician). Have a six-year factory warranty covering motor. No advantage to changing tach other than looks.

Has anyone swapped from a non SDS prop to the SDS prop? I am getting a vibration just in gear that resonates throughout boat. My hope is Shift Dampening System prop would cure this.

 

[DennisG01]

1. Check height of anti-cavitation plate on plane. Just a small point for clarification... it's an anti-venitilation plate. Cavitation is an entirely different thing.
2. Trim motor out fully when checking for max RPM’s Just in case you weren't aware... keep trimming up till the speed no longer increases or the prop starts to venitilate. Just before that point is your MAX RPM for the current load.
3. Reconsider Yamaha USA motor break-in (hour two was sJpent varying between off plane load and WOT).
4. Tach compatibility was confirmed and is it designed for both 2-stroke and 4-stroke motors and all warning indicators as well as other functions work correctly for the new motor (per Yamaha Factory Authorized Technician). Have a six-year factory warranty covering motor. No advantage to changing tach other than looks.

Has anyone swapped from a non SDS prop to the SDS prop? I am getting a vibration just in gear that resonates throughout boat. My hope is Shift Dampening System prop would cure this. I have not, but just wondering outloud... Why does Yamaha need this or offer a "non" SDS prop? I mean, if there's an issue with the prop, why not just make them ALL SDS? I would think, though, that once the load is on the propeller (in gear) that any rattle or vibration should be eliminated? Maybe double check the prop and thrust washer are on correctly? How does the prop feel if you play with it with your hand?

 

[Lite Tackle]

Yup typo (cavitation vs. ventilation), coffee not kicked in. Thirty years of running outboard boats, got the whole trim thing down. Dennis, you are very detail orientated. Still think Jim over at Continuous Wave has you beat though .
I appreciate your input.

 

[DennisG01]

Yup typo (cavitation vs. ventilation), coffee not kicked in. Thirty years of running outboard boats, got the whole trim thing down. Dennis, you are very detail orientated. Still think Jim over at Continuous Wave has you beat though .
I appreciate your input.

Thanks... I think... Just kidding - have a great New Year! And remember... all of the problems we experience with our boats... are GOOD problems! There are much worse problems to have in life.

 

[leeccoll]

Yep, and I just edited my suggestions, as this is all very captivating to me

 

[PNW_Drifter]

Very interesting to me and I'm about to swap my 200 HPDI for a fourstroke 225hp motor. Concerned about scuppers. Thanks for letting us know.

What does the GPS antenna do for you? I thought all the newer GPS's don't need antennas besides internal? I ask because I found a few old Lowrance and Garmin antennas on my boat that I want to remove. Maybe I shouldn't'?

Keep the updates coming!

 

[Lite Tackle]

Last time out with the boat I got a good look at the anti-ventilation plate and it appeared just under the surface. I had asked the shop to raise my motor during the 20 hour service and they stated they were not comfortable raising motor and when measured against hull that it was perfect where it was. I trust the shop, so now I’m confused about whether or not to raise motor now. Researching props, I am leaning toward the 15 x 15 Mercury Enertia or 15 3/4 x 15 Mirage Plus though I was looking forward to the shift damping of the Yamaha prop.

The GPS antenna is the Point-1. It provides extremely accurate and rapid boat position and speed updates. In addition, unlike other position-only antennas, the Point-1 provides heading for accurate boat direction at any speed and for radar/chart overlay. Integrated electronic compass with GPS provides vessel heading with rate stabilization that provides heading output for accurate chart orientation in the Heading Up mode, improved Course Over Ground at low speed, and radar overlay. Excellent time-to-first-fix, with 10Hz, multi-GNSS, high-speed updates - up to 10 times per second - for smoother and more accurate location updates. (End of commercial).

 

[DennisG01]

Not so sure I agree with your shop. Measuring on land is one thing, but real life experience is another. You had real life experience showing the plate was under water - that trumps measuring on land. Whether raising it will make the difference you are looking for, or not, has to be done to be seen. But I do think this step should be taken first.

 

[Halfhitch]

Lite Tackle, In one of your earlier posts in this thread you mentioned a vibration at idle speed. I have the same engine only in 225 flavor. I also experienced that and did some research. That noise and vibration is an occurrence called, " prop rattle". It is caused by sudden changes in the rotation speed of the prop shaft. At dead idle, each time a cylinder fires there is a sudden acceleration of the crankshaft due to its' relatively slow speed. These engines being 4 stroke don't fire every upstroke of the piston so the crankshaft coasts a millisecond or two, enough to begin to lose some rotational speed. Then the next cylinder fires and it starts all over again with a surge of speed of the shaft. So whats making the noise/vibration is the rapid speed up/slow down cycles of the prop shaft. There is some clearance tolerances in the shaft splines to prop splines. This causes the splines of the prop shaft to slam into the splines of the prop when a cylinder fires at idle, then the prop is up to the shaft speed but then the shaft slows a bit so the heavy stainless prop coasts ahead causing the spline to come tight in the opposite side of the spline, then the next cylinder fires and it starts all over. Knock, knock, knock, knock...…..until you get on the throttle a bit shortening the time interval between firings of the pistons and adding water resistance against the prop so it can't coast ahead of the shaft and holds constant contact against the splines. That's what I have come to understand after reading a lot on this. I thought I had a bad engine. The F150 inline 4 cylinder is worse than the 6 cylinder they say. Read up on prop rattle.

On another subject. I am curious if I am getting full throttle on my engine. I took a picture of my throttle linkage with the lever at full. There are two marks you can see that line up but there is more space before that round plate makes contact with the stop like my old engine. If you are messing around your engine with the cowl off would you take a look at yours when at full throttle setting and see if it has the marks lineing up or is it hitting the stop. Thanks

 

[Lite Tackle]

Dennis, thanks for your thoughts. I agree. I may attempt raising motor myself before considering prop change.

Halfhitch, nice lesson. My understanding is clearer now. Vibration is not bad, nor is the shift clunk, but if it could be reduced, all the better.
I’ll get a look at the linkage ASAP and report back.

thanks guys

 

[DennisG01]

Dennis, thanks for your thoughts. I agree. I may attempt raising motor myself before considering prop change.

Halfhitch, nice lesson. My understanding is clearer now. Vibration is not bad, nor is the shift clunk, but if it could be reduced, all the better.
I’ll get a look at the linkage ASAP and report back.

thanks guys

A $30 come-a-long will do the trick. A large, overhead tree branch will work. Or, in a garage, put an eye bolt through the ceiling and into a 4x4 that spans a couple rafters. When you break it down, you're only lifting 5 or 6 hundred pounds and it's just 4 nuts to remove.