yamaha 2002 115 2 stroke

[njohnson1960]

I have a yamaha 115 2 stroke engine. I have replaced the prop three times thinking I had a bad prop running 13 x 19K prop which is original one outfitted when I bought boat 3 years ago. Engine only has 100 hours on it. My problem is when I am at about 2800 RPM I get forward movement as soon as I try to get up on plane and increase throttle The transom seems to sink down and the bow rises up and I Don't get thrust forward then the RPM's climb way too high without much forward movement. If I equate this sound to a car it sound like the transmission is slipping out of gear and into neutral with the gas pedal applied. HELP anyone, is my lower unit screwed up? I dod not hit anything to the best of my knowledge.

 

[rodbolt]

Re: yamaha 2002 115 2 stroke

a quick run with the YB1626 test wheel will eliminate a lot of possible issues.
would be one of my first steps in diagnosing an engine issue.

 

[njohnson1960]

Re: yamaha 2002 115 2 stroke

Where do I get one and for what $$$ I have replaced the original 13 x 19 K with a brand new one and it used to run great the first year I got the motor with that wheel. I cannot keep buying wheels to try out. The last guy I bought the wheel from let me try out a 13 x 17 telling me that should solve the problem, it didn't so he swapped it for a new original YAMAHA 13 x 19 K wheel. The boat reacted the same way.
Is it a do it yourself job to drop the lower unit and open it up to take a look at the gears to see if anything is ripped up?

 

[njohnson1960]

Re: yamaha 2002 115 2 stroke

By the way Cadet, thanks for answering me you're the only one so far who has. This really has me turned around, I can't figure it out. Spoke to several Yamaha shops locally and they don't have the time to take a test run to hear the engine and give me an evaluation of what's going on. 4 yr old motor with 100 hours on it shouldn't be having this problem already. (Bought it in Nov of '03, didn't use it until Apr of '04.)

 

[Larcus]

Re: yamaha 2002 115 2 stroke

Some boats have foam under the floor, if it gets wet it will not dry out. If your boat has been sitting outside that may be the problem. Maybe you could weight it if you know what it should weight. My bass boat acts just like when I forget to put the plug in.
Larcus

 

[rodbolt]

Re: yamaha 2002 115 2 stroke

find a dealer that will let you borrow the test wheel, install the test wheel like a standard prop. back it in the water, warm up the engine place it in fwd gear ,go full throttle with a known good tachometer and see if it will spin it.
test specs are in the tune up spec guide along with the test wheel part number.
this will save a lot of time and wasted money seperating hull/prop issues from engine issues.

 

[njohnson1960]

Re: yamaha 2002 115 2 stroke

Thanks for your help guys. I will bring it in to the dealer and see if they are willing to test the boat with this test wheel on it. And I will check to see if the boat is holding any water weight in the foam. I have a 2004 Aquasport CC and there is definitely foam under the deck. And in addition there are areas that I thought should have been filled with foam that are void of any and they hold pools of water. Checked my bilge area to see there was a blockage and water was sitting in there, it was dry. We haven't had any rain here in weeks durng the summer. It's all dry down there as far as I can tell.
I put the boat in gear last night and tried to move the wheel by hand to see if there was anything that felt loose in the gear train. I just turned the motor with no give or freeplay. So I don't think it's the lower unit.

Can't figure this one out on my own. Guess I'll have to bring it over to the dealer and see if he can scratch his head for awhile on it.

 

[rodbolt]

Re: yamaha 2002 115 2 stroke

look on the dealers wall for school certs, should have,at a minimum, outboard systems,Fuel and electrical.
if ya dont see them find a real dealer.
but a quick spin up with a test wheel eliminates a lot of potential issues.

 

[Margarita Man]

Re: yamaha 2002 115 2 stroke

Do you have hydrofoil fins to keep the bow down when you go higher rpm's? How is your cavitation plate in relation to the bottom of the hull? How is your trim position, are you trimmed down when you give power? I would check these conditions before taking the motor apart and buying more props.

 

[njohnson1960]

Re: yamaha 2002 115 2 stroke

Thanks, Cavitation plate is just below Hull bottom keel line. Don't have hydrofoils but never needed them before. Spoke to a mechanic he thinks I may have slipping in the driveline. Either a 2 part driveshaft coupling or may be lower unit. He's going to pull the lower unit and take a look.
The problems are growing though. Now my trim motor wasn;t working all of a sudden, I checked the wiring to the trim motor and found one of the wires was corroded and pulled right out of the trim motor. Then went to check the engine and wasn't getting any engine info back at the helm. Seemed like my battery was dead. But checked that and it is fully charged. Checked main fuse at battery and that is OK. I'm scratching my head now big time. Time to ask a mechanic for HELP. I can't figure this out anymore.

 

[rodbolt]

Re: yamaha 2002 115 2 stroke

a sucker is born every minute.
your grease monkey is poking and hopeing, but at least you will pay for the kids school clothes.

 

[njohnson1960]

Re: yamaha 2002 115 2 stroke

Figured out all of the problems with exception of the Lower unit "slipping" issue. Fuse (20A) in the carrier under the fuse (30A) was just barely fried. Replaced and all of my electronics came back on at the helm. Guess that supplies power to the engine computer (CDI) unit. They give you an extra fuse sealed in a vinyl pouch attached to both inline fuses. Guess they are pretty important. By the way does anyone know what CODE fuse they are? They're not marked like auto fuses AGC, MDL, etc. Different length than a regular fuse. The four bolts I needed to replace after pulling the trim motor out will cost me $30.00 from Yamaha. I would hate to pay $20 for a fuse, this company is kidding. Does anyone know where an E-Tec Dealer is?
Had my Trim Motor rebuilt at an electric motor rebuilding shop here in NY for $50.00. A lot less than the $165 for a replacement ARCO or $500.00 for a real Yami part.
Keep your eyes open guys or Yamaha is likely to empty your wallet faster than you can keep up.