Johnson, Evinrude, OMC, outboard motor, outboard motor repair, 9.9, 15 hp, date/year of manufacture, water pump, carburetor, long shaft, 15 hp conversion, sailmaster

Since I am more familiar with the 9.9/15hp motors, I will try to identify the differences between this 8hp motor & the 9.9s.   I have had the use of this 1992 motor to use & examine it, so the following are my observations.  It trolled all day long (7 hours) at a faster salmon trolling speed on 3 gallons of fuel.  This motor would be a good choice for a lake trolling motor, but for even a 16' boat trolling for a bay type fishery where the current & or wind is prevalent, it just does not have the thrust to contend with the wind unless you speed it up considerably to counteract & keep it on course.

In the upper banner the picture on the left is 1992 to 1997.   The motor I will be describing was made in 1992.   These motors have a new designed recoil starter that bolts onto the upper part of the motor similar to the post 92 9.9/15hp motors.   This one has on the nameplate made in Belgium, & another motor I observed did also, however they both were sold in the US.  The connection to Belgium is not known, unless this was the first of the new design & was made there before the US could gear up for it on that model.   Upon later tracking things down, it appears that this series of motors were made in either Belgium or Hong Kong.

The water indicator hole tube comes off the left side's upper water jacket.

There is no "Flush Plug" on the block to flush the motor thru.

The thermostat is on top of the head like the 86 & later 9.9s.

The lower cowlings are made of plastic & similar to the 93 & newer motors, & uses the same basic upper cowling rear latch as the 93  9.9.   There are no side cowling bumpers to protect the motor, but has rubber leveling pads on the rear of the lower cowling for support if the motor is laid on it's rear.

Year of Manufacture :  This is important in any repair, for obvious reasons.  Prior to 1979, Johnson used the last 2 digits of the year in the model number.  As a model 6R78M, would indicate a 6 hp, Rope starter, 1978 year of manufacture & M model revision.  Since this does not have in the code L between the hp designation & the year, it is a short shaft version.   Evinrude in those years used a different 5 digit model code, as 6424S.  The numbers  you are looking for will be the first 3 numbers which equates to the hp & then the middle to the year, as 6 hp, the (4) equates to 1974 & the (S )would indicate a shorts shaft.  Here is a LINK to help you determine any of the Johnsons.  And here is the LINK for the Evinrudes.  For those of you readers outside of the United States, here is another LINK that may better help with your motors.

After 1979, OMC's manufacturing year code, which included Evinrude, is the word "INTRODUCES", with each letter equating to a number ie:  I=1, N=2, T=3, R=4, etc. as illustrated below.  As before, the last 3 letters are what you are looking for.  Then in this case, disregard the last one, as it pertains only to a model revision that only on specific cases may be revalent to a marine repairman if problems arise.  A code of  J10ELENA would equate to Johnson, 10hp, Electric start, Long 20" shaft, EN = 1992, & the A could be a model revision, so this motor would probably be made in the very first part of the year.  You may encounter a code of something similar to J10SELCTC. This would have been  Johnson, 10hp, SailMaster, Electric start, Extra Long shaft, 1983, & the C could be a model revision.  In this case with the SE in the model number, indicating a SailMaster, all the SailMasters would have all had the extra long 25" shaft.   For more detailed information on worldwide production, CLICK HERE

Using this code system, if the motor was sold as an Evinrude, then the first letter would have been an E instead of the J.   Then you can encounter motors made in or for other countries, which will have some added letters as mentioned later in this article.

Sometimes the nameplate found on the LH side of the upper steering/clamping bracket can get removed.  If this happens, you can still usually tell which motor it is by looking at the 25 cent size soft plug in the upper rear RH side of the block.  The model & year are stamped in this soft plug also but probably only up to 1979.  It is interesting to also note that the 6 hp uses the same block as the 8hp, so you could see either hp with the same 6R78M numbers here as the 8hp has.   You may find that the plug numbers do not match any of the codes, as the factory changed things as time went on.

Exploded Parts Lists : For a internet link to a marine parts seller CLICK HERE  that has exploded views as shown below in this article.    From this business, you can identify the numbered parts & purchase parts online from them. 

Front view	Rear view

The twist grip throttle & kill button are very similar to the 9.9 with the exception that the kill button is mounted in the handle about mid section & does not angle like the 9.9s, but is set at 90 degrees to the handle.  It also has a friction lock on the throttle similar to the Sail-Master 9.9s.   The choke lever is in the same basic location, but is shaped different.  There is a carrying handle mounted between the clamp screws that pivots forward.

Electronics : The electronics uses the Capacitor Discharge type with a powerpack up until about 1990, after that it was changed to the Under The Flywheel type.

Under Flywheel electronic ignition system

 

Timing plate assembly

Manual Starter : You will notice the newer type manual starter & flywheel similar to the 1993 & newer 9.9 motors.  The throttle linkage again is very similar also.

Left side	Right side

Carburetor : The carburetors appear to be virtually identical for both the 6 & 8hp, with only a possible larger main jet for the 8hp & larger throat.  These carburetors from 86 on had plastic top covers & also plastic bottom fuel/float bowls.  About mid 1987 the idle jet was moved from the front center of the top cover, to the rear RH side (facing forward).  The old front idle jet hole was plugged with a screw of the same size as the old jet threads & a gasket under the screw head.  This new idle jet is smaller in diameter & is angled from the upper outside down into about the center of the plastic top.

It appears that this new style top cover could be used for either idle jets depending on the version or placement of the breather.

The top cover is threaded at the rear on the top LH side for the throttle arm pivot point screw.  Shown below the 2 top holes that are empty are used to hold the air breather on in addition to adding extra top cover screws.

Carburetor off a late 87 and newer

Fuel Pump: These fuel pumps are pretty universal, the same small square one fitting most all these small motors up to 40 hp until about 1987 depending on the size or version of motor.   This model appears to not have moved up to the newer fuel pump used on the larger motors of the same time frame.  For a link to the rebuild procedure CLICK HERE.   These motors use the single fuel line & the standard OMC quick couplers.

Recommended Fuel / Oil Mix:   The formula shown below will be on all modern 2 cycle oil sold in the last 30 years or so.  On most all of the pints & quart plastic bottles of TWC-3 oils there will be a narrow clear vertical window on the edge of the bottles.  On the sides of this window will have numbers representing ounces & Milliliters for other parts of the world.  Or you can purchase special measuring containers showing different ratios & the amount of ounces needed.

If your motor is to where you have to mix the oil, you need to know how much gasoline you will be needing, add the oil before you fill the fuel tank so that the oil mixes better that just dumping it in after you fuel up.  However if that is not possible, guess, & add a majority of what you think it will take, fuel up & then add the rest matching the amount of gasoline you took on.  If you are using portable fuel thanks, before hand, when you fill it, add 1 gallon at a time, use a clean 3/8" or 1/2" dowel & mark the dowel at each gallon & use it as a measuring stick.  This way you can refill a partly full tank with the known amount of oil.

A quart has 32 ounces of oil in it.  So for a portable 6 gallon tank to fill it using the 50:1 ratio would take 16 ounces, (1 pint) or 1/2 of the quart.

The official OMC fuel/oil mix for most outboard motors in this year ranges has for years been 50:1.  This means 50 parts of regular gasoline to 1 part of outboard motor oil.  Remember that this was before unleaded gasoline or even possibly an octane rating that was listed at the pumps.  Now the recommended fuel is 87 octane gasoline.   Or before the outboard industry came up with any TWC oil, much less the latest which is TWC-3 outboard motor oil.  You probably will not see much of the older TWC-2 oil out there anymore.  You can spend your money & purchase OMC oil for about $6.50 a quart, or buy a name brand quart for $2.79.  Sure the manufacturers want you to buy their oil, & for a new motor under warranty, it may be advisable to do so.  But the consensus from many experienced boaters is to use any good brand of oil, as long as it has the TWC-3  rating, it meets or exceeds the manufacturers specifications.  The TWC-3 represents,  Two cycle, Water Cooled, type 3 formula.  The formula 3 has decarbonizing additives designed to be more compatible with the newer non-leaded fuel.

So from the above information, you can see that fuel & oils have changed dramatically since these motors were first brought out in 1974.  In this instance, times have changed for the good, as we now have a better gasoline & way better outboard oils.

Fuel/oil mix on all the OMC motors that have needle roller bearings is 50-1 of TCW-3 standard outboard oil.  However I have found that since I troll much of the time, other than getting there & back, I like to use a mix of 75-1 but of a SYNTHETIC blend oil instead of the standard oil.  This gives me at least the same or better motor lubrication, plus it gives me less smoke at a troll & the spark plugs last longer before fouling.

Midsection / Shifting: This 92 motor uses the newer type front mounted shifting lever & most other associated parts as the 93 & later 9.9 motors.  The lifting / carrying lever is similar to the 93  9.9s.  The tilting lock lever rotates as with the previous model.
 

Exploded view of Midsection

One thing was experienced is that the shifting lever HAS to be in neutral, otherwise if the starter rope is pulled, it may stick in the pulled position.  It usually can be convinced to retract by moving the shifting lever to neutral, or into reverse & then back to neutral again.

Water Pump : The water pump is essentially the same as most small OMC motors of this era.  The disassembly of the lower unit to replace the impeller is that the shifting rod rotates as with the previous model instead of moving up & down.  It is connected by a spline on the upper shifting rod end to the shifter lever unit under the carburetor.

Lower Unit : The lower unit is a unitized design smaller than the 9.9 & does not use the thru the hub exhaust.  The water intake is in the exhaust tube right behind the prop as used in the older smaller OMC engines as seen by the screen hanging down in the photo below.   And it offers no real opportunity to attach a flushing attachment.  The prop has a shear pin & the plastic bullet nose is just a retainer that is held in place by the cotter-pin.

This lower unit comes apart similar to the 9.9 for water pump repairs, except there is no shifting rod link coupler & screw.  This motor does not use a vertical movement shifting rod, but a rotating one.  The shifting rod comes off when you take off the lower unit.  It has a flat on the upper end that engages into a slot in the pivoting shifting linkage inside the housing

Lower unit & prop	Nameplate

For flushing or running this motor out of the water, you will need to put it in a barrel as the company that made flushettes for motors like yours called it quits a few years ago (Tempo Products).

Propeller :  The prop has a shear pin & the plastic bullet nose is just a retainer that is held in place by the cotter-pin.    
OMC / Bombardier  #390237 — propeller, (Part replaced by OMC 0778797)   8-1/2" X 9" 3 blade, (5/6/8hp models) EXCEPT long shaft models which use a different one.    Or Michigan Wheel propeller, 1980 & newer Johnson 6 / 8hp #012032 8 1/2" X 9, 3 blade $81.99
 

As for repairs, it seems to be a very simple proven design that by my limited exposure to it the only thing I see a detriment is that you need a special flush unit as the regular muffs will not function.

Copyright © 2007 - 2011  LeeRoy Wisner  All Rights Reserved

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Originally stated 09-16-2007, Last Updated 12-12-2011
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