20 Most Recent Clymer Marine Maintenance and Repair Manual '99 '02 Yamaha 115 250 HP 2 stroke Outboards Questions & Answers

If your 115 Yamaha SHO VMAX outboard engine is experiencing RPM fluctuations at speeds over 3500 RPM, it may be due to a few different factors. Here are some things to check:

1. Fuel supply: Make sure that the fuel supply to the engine is consistent and free from any debris or obstructions. Check the fuel filters, fuel lines, and fuel pump for any signs of damage or clogging.
2. Spark plugs: Check the spark plugs to make sure they are clean and functioning properly. If the spark plugs are worn or dirty, they may cause the engine to misfire at higher RPMs.
3. Throttle position sensor: The throttle position sensor (TPS) sends a signal to the engine control module (ECM) to adjust the fuel and air mixture. If the TPS is not functioning correctly, it may cause the engine to fluctuate at higher RPMs.
4. Air intake system: Make sure that the air intake system is clean and free from any debris or obstructions. Check the air filter and air intake hoses for any signs of damage or clogging.
5. ECM software updates: Check with your Yamaha dealer to see if there are any available software updates for the ECM that may improve the engine's performance.

If you are unable to diagnose and fix the issue on your own, it may be necessary to take the engine to a professional technician for further diagnosis and repair.

Look below lower mountings you will see the shift rod with along nut and a lock nut,undo long nut,do this with motor in reverse gear,some 40s have a stainless plate cover which you have to remove first

gap at .032" - .035" max

You might have a magnet issue(under the flywheel).. it happened to me.. one was loose..

do and online search and include year --

very basic carbs ! clean all jets and emulsion tube then check the float needle is clean and the tip isnt grooved , blow threw all ports etc and then refit and set the mix screw 1.5 turns out for starters then run up in a tub of water and fine tune till its happy to idle and rev up ! make of engine ??

Check your battery wires. If the battery disconnects even for one second or the grounds are bad then the stator has no where to put the charge and it will fry.

67H-83672-00-00 All models uses the same unit since 2004 ( from 30 to 300hp)

Hello, you'll need a second wire harness for the instruments. And also a hose for the speedometer.

Unscrew the 4 idle mixture screws 1/2 turn 1 at the time till sneezing stops... Clean your carburettors

Engine or gearcase seized... Remove the recoil starter ( 3 bolts and the startingear link) If you can turn the flywheel slightly: Gearcase seized If you can't turn the flywheel at all: Engine seized. In both cases: If you can't disassemble and have the job done yourself, forget that motor...

First thing to check: Disconnect the tiny hose between the check outlet and the engine. Disconnect it at the engine side. With an airgun, blow in the check hole from outside to engine side. With an airgun, blow out the engine connection. Start the engine, check waterflow out of the engine connector. If water, reconnect the hose and check the water at the checkpoint. If still no water at the engine connection: replace the impeller!

Nice engine

That's a current problem. OR the screw is rusted in place. So then use WD40 or eqivalent to free the screw. Or the parts inside are worn. Remove the friction screw. Then, remove the 4 bolts holding the swivel cap. Remove the entire engine from the swivel to prevent it fall on the ground. Replace the worn parts.

Have you checked manualslib.com?

BR7HS-10 (1mm gap)

Sounds like it has a fuel restriction. Hook up a fuel pressure gauge on the vst tank on the motor to make sure you have 30-50 lbs of fuel pressure.