Yamaha 9.9 – The Yamaha 9.9 4 Stroke Outboard Motor

It was finally time to think about replacing my current outboard engine.  I’d had the Johnson 6hp 2 stroke outboard motor for a couple of years now and it had served me well during that time.  In fact it only failed to start once during that period, which, considering it hadn’t been serviced whilst in my ownership was quite impressive.  Looking at the market it was clear that a 4 stroke was the choice for my next purchase.  I’d got to the point where mixing oil with the fuel had become cumbersome and trying to remember which canisters were mixed, which weren’t and was it 50:1 or 100:1 fuel oil mix?  The benefits of 4 stroke seemed too good to pass up.  Having already purchased a 3.5hp Mercury in the past and currently owning a Yamaha 2.5hp 4 stroke I was already aware of some of the benefits including quieter running and better fuel efficiency.  

Time for an afternoon on Google to see what’s available.  The plan was to search out a suitable 9.9hp 4 stroke.  Looking at the second hand prices I didn’t see the point of buying second hand when you could buy new for just a few hundred pounds more.  In fact I was quite amazed that the second hand ones sell for those crazy prices.  Second-hand examples are currently being listed for £1200 to £1300 with no warranty whereas a brand new ones are available for £1600 or so with full 3 or 5 year warranty.  Looking at the 9.9hp models by Yamaha, Mercury, Suzuki and the Honda (10hp), I was keen to compare the weight of each, not just price seeing I would be lifting this engine on and off the boat every outing.  The prices I found here were on-line in the UK in the month of April 2016.  Obviously my choice was made based on the figures here and as you would expect, prices fluctuate so a different month may have resulted in a different purchase.

Yamaha 9.9 hp  Price    £1600    Weight  39KG

Mercury 9.9 hp  Price   £1908    Weight  38KG

Suzuki   9.9 hp  Price    £2028    Weight  39.5KG

Honda    10 hp   Price   £1917      Weight  42KG

This was my thought process when deciding.  Looking at the weights,  the Honda was a little too heavy and as for the prices the Suzuki was a bit too pricey in comparison.  I’m sure the Suzuki and Honda are fantastic motors but didn’t suit my requirements on this occasion.  That left 2 contenders, the Mercury and the Yamaha.  I eventually decided on the Yamaha 9.9, firstly there was a Yamaha promotion running offering 20 percent off the list price and secondly it had a rather clever flushing pipe which would mean no more starting the engine to flush it out.  I can simply attach a garden hose and flush the system without starting it.  That should please the neighbours as there’ll be no more starting of engines late into the evening after a day out on the boat.  You could argue that the other 3 motors have longer warranties so can justify the extra cost but for me that isn’t an issue as I never keep a motor for more than a few years anyway.  With the outboard now ordered I just had to wait on it’s arrival.

2 days later and the Yamaha 9.9 outboard has now arrived.  With the outboard unpacked the first task was to add the oil.  It arrived empty as this was removed after the initial PDI (Pre Delivery Inspection) by the supplier.   Now filled, it was time for it’s first start up.  Here is the un-boxing and first start up video:



  The video below is of the Yamaha 9.9 outboard running in a tank about to start the 1st hour running in period.



There is a running in process to follow.  1st hour run at varying speeds up to half throttle, 2nd hour varying speeds but avoiding full throttle then the next 8 hours run at any speed but avoid using full throttle for more than 5 minutes at a time.  After that run as normal.  I decided to do the first hour of the running period in a tank of water keeping it mostly on quarter throttle in forward gear then every now and again reducing and increasing the revs but not exceeding half throttle as per the running in instructions.

Yamaha 9.9 - The Yamaha 9.9 4 Stroke Outboard Motor on Seapro


 Yamaha 9.9 Outboard Motor Specs:

Yamaha F9.9JMHS

Engine Type Two-Cylinder

Displacement 212 cc (12.9 ci)

Bore x Stroke F9.9 – 56 x 43mm | 2.20 x 1.70in T9.9 – 56 x 42mm | 2.20 x 1.69in

Prop Shaft Horsepower 9.9hp @ 5500rpm

Compression Ratio 9.46:1

Fuel Induction SOHC

Exhaust Through Propeller

Intake Carburetor

Ignition CDI Micro Computer

Spark Plug BR6HS-10

Alternator Output 6 Amp (requires optional rectifier/regulator)

Starting System M = Manual | E = Electric

Lubrication Wet Sump

Engine Oil Capacity 0.8L (0.85 qt)

Full Throttle RPM Range 5000 ~ 6000 rpm

Cooling Water/Thermostatic Control

Recommended Engine Oil Yamalube® 4M (See owner’s manual)

Recommended Fuel Regular Unleaded (Minimum Pump Octane 87)

Recommended Fuel Filtration Yamaha Mini 10-Micron Fuel/Water Separating Filter (external)

Ethanol Blend Limit 10% Maximum

Gear Ratio (27:13) 2.08:1

Gear Shift Forward, Neutral, Reverse

Shaft Length S=15″ L=20″ X=25″

Degree of Tilt 71°

Degree of Trim 4 positions

C.A.R.B. Rating 3-Star

Dry Weight F9.9SMHB = 39kg (87lbs) F9.9LMHB = 40kg (89 lbs) F9.9LEB = 42kg (93lbs)

Steering Angle (maximum) F9.9 – 43° from center, either direction T9.9 – 38° from center, either direction

Warranty 3 Year Limited Pleasure Boat – 1 Year Limited Commercial

Yamaha Outboards:  https://yamahaoutboards.com/en-us/

Our first outing using the Yamaha 9.9 outboard motor: https://stufishing.com/running-yamaha-9…4-strokeoutboard/

6 thoughts on “Yamaha 9.9 – The Yamaha 9.9 4 Stroke Outboard Motor

  • June 24, 2017 at 9:02 pm

    Whats that weight like to carry and fit to the back of the boat ?


    • July 2, 2017 at 7:36 pm

      Hi Phil,

      For me it’s a bit on the heavy side. So I suppose it depends how strong you are. It’s 43KG and I struggle with it sometimes. It’s the main reason why I will be downgrading to a 6hp (23-25KG) this year or next. With a 6 it probably won’t plane so won’t be particularly fast but I don’t need much speed for what I do.


  • July 24, 2017 at 9:10 am

    Where did you buy the engine from? Thinking of buying one myself for the right price

    • July 30, 2017 at 1:02 pm

      Hi David,

      I bought this engine from Seamark Nunn. Yamaha were doing a 20 percent discount at the time. Not sure what they are going for now though.

      Regards Stuart

  • August 8, 2017 at 12:52 am

    You need tof put videos of oIL changing and more about motor . YaMaha don’t have any videos. I found you in YouTube. Please put more videos

    • August 29, 2017 at 6:45 pm

      Hi Dany, yes good idea. When they are due for servicing I’ll make a video.

      Regards Stuart


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