2005 F150 will not plane out

[CecilR1800]

Hi, Brand spankin new to the Yamaha Parts Forum. My Boat (1989 Robalo R1800) will not plane out unless someone walks to the bow. I am trimmed all the way down, but still struggles to pull the boat out of the water. Once on a plane, The boat is running at 4000 RPMs (WOT) laid down. My manual says that the engine is suppose to run between 5000-6000 RPMs at WOT. Some information about my rig:

2005 Yamaha F150
Mounting pos. #05 (highest postition) - Cavitation is 1.5 inches higher than Keel
14x19 Solas SS prop (some say I need a 15x17 - Less pitch more Dia) but I would only gain 400 rpms - Im told
18' Robalo Hull - Center Console
20" Transon height
55 gallon tank
Boat is 2000 lbs dry - I imagine near 3800 loaded down (fuel & gear & 2 people)
The previous owner recently had an external fuel/water separator installed (original tank I imagine) - He said it was "recommended." He also mentioned something about "rings were clogged, but were fixed." Rings? is this somehow related to the injectors? I read on another forum that the small filters on injectors can be cleaned. Is this something that I can take on myself?

Operating Hours
0000-1000 RPM - 31.7 hrs
1000-2000 RPM - 2.8 hrs
2000-3000 RPM - 83.0 hrs
3000-4000 RPM - 83.0 hrs
4000-5000 RPM - 9.7 hrs
5000-6000 RPM - 0.0 hrs


Been around boats my whole life but this is my first time as a boat owner. Any help/advice would be greatly appreciated. Tight lines and thanks for reading my post.

Jarrid

[boats.net]

I would be worried about the "Rings" being clogged, check engine compression to see if rings are ok. Check engine mounting hieght, for a 20" transom motor model should be be F150TLR("L" for 20", "X" for 25").

[CecilR1800]

Rings and Mounting height

Thanks for the response. The engine is the F150TLRD...so 20". They guy I bought it from said that it was in mounting postioin #2 up until a month before I bought it. He had it lifted to (correction from the original post) position #4 as a recommendation from his prop guy.

Would the rings be something that I could clean or replace myself?

[501nmc]

Yamaha makes a conditioner for the rings, it is called ring free (I think). U can find it at your local marine retailer. Follow the directions! You can pour it into your crankcase and run for a little bit, but have to change the oil. You can also run along with gasoline to clean the combustion side. I prefer to run seafoam on the combustion side.
Fought the bow rise problem myself. I had to set the cav plate about 3/4 inch from keel to help with planing. Most people on different web pages recommend being even with the bottom of keel and you can move the motor up about 1in for every 10mph over 40. If you run 50mph then you can set your cav plate at 1in above the keel and so on. Low rpms could be your prop. your history shows that you have never run in the 5000 to 6000 range, the person before you may have never had the right prop for the application.

[DT]

2005 F150 will not plane out

I have a 20' 1985 SeaOx - walk around cuddy with a F150 2005 4 stroke - the boat taps out at 40mph at 5700 rpm with a 14 1/4 x 17" Reliance stainless steel prop. I had a 14 1/2 x 17" aluminum prop and got the same top speed but it comes out of the shoot sluggish. The boat has a 55 gal tank, 2 giant 12v batteries and assorted fishing gear... and we all SeaOx's are very and weighs around 3500 lbs - I have 840 hrs on the motor and it still runs like a clock. Fuel economy is between 3 and 4 gal an hr. hopefully this will help you out.

[CecilR1800]

Rings and Prop

501nmc,
Thanks for the rsponse. I will try the ring free in the crank case to see if this helps. I will keep you posted. I added Seafoam to the gas tank on Saturday, but I have not run the boat since then. On the Yamaha 10 micron fuel/water separater I read that you should replace it every 50 to 100 hours, but the initial filter should be changed after the first trip. Being that this filter system is brand new to the vessel (and about 6 trips on it) I plan to replace this today. Regarding your cav plate - Was this a lift or a lower on the mounting position?..Just Curious. Thanks again.

DT,
Thanks for the response. After I do get on a plane I max out at 4,000 to 4,200 RPMS so I definitly have power loss as well as prop issues. I was thinking about going with a 17 pitch like you mentioned below. Probably Aluminum first before I make the SS investment. What is your routine? No clogged injectors? VST? what region do you boat? Thanks DT.

[DT]

2005 F150 will not plane out

We run our boat out of Staten Island, NY. The bottom of the boat is not painted since I trailer it. I do use a Mercury water separator filter and I change it once a year. I also change the filter on the motor once a year. I don't believe you have a piston ring problem, the four strokes don't run into sticky rings or gummy rings if you take care of the oil and engine filter. I believe you could have a problem with your fuel flow. I would try the Mercury water separator filter. Let me know what region you are from.

[mitch]

Cecil wooha the ring frree goes in your fuel the same seafoam

[CecilR1800]

So, Ring free in the Crank case is a no go?

Do I understand this correctly?

THanks Mitch.

[CecilR1800]

2005 F150 will not plane out

DT, I run out of Ocean Springs, MS - Gulf Coast. "Oil Spill region."

Thanks for the advice. Here goes nothing (Trying to post a picture of my rig)............

[501nmc]

You can run the ring free in the crankcase. The directions will tell you that you can. You can only run it for a little while and you have to change the engine oil afterward, u can't leave the ring free in the crankcase. The seafoam takes the place of the ring free in the gasoline. Seafoam is about $8 a can at walmart and treats 20 gal. Ring free is about $16 a can. The cav plate goes up for every 10mph over 40. If you are wondering about the prop size, you can visit mercury marine.com. They have a prop calculator that will suggest different types of props for your application. There are other calculators out there, you can search prop calculator and it will take you to one that you can put your specifications into and it will suggest the proper prop. Once you find the right prop, or a different one, you can calculate your slip to see how effecient the one you have is. The calculation is Pitch X RPMs divided by 1056 and then by your lower unit gear ratio. You will have to research the gear ratio with yamaha. Yours is probably a 1.86 to one, but not sure. I run a 90 fourstroke an mine is 2.31 to one. Prop slip will tell you how much your prop is cavitating and will help with your trim and height reference. Most places that I have searched say 10% is average, but you can achieve lower say 5 or 6%. You can pull your spark plugs to check for fuel problems, white is too lean, black is too rich, its a fourstroke, it shouldn't be much different than your truck. Hope this helps.