JOHNSON 18 HP FD-11

I have a 18hp Johnson fd-11 that was sitting in a garage for 20 years. im try to restore it to its original glory put im hitting a few snags. I don't think i can buy a rebuild kit for the whole motor and i know all the seals need replacing and the carb needs cleaning. I also have a situation with the bolt on the top of the crankshaft wanting to cross thread and i cant seem to get it straight. I have not looked at the lower unit yet but I imagine im in for a treat. This is my first motor rebuild but im having a lot of fun with it, if anyone has any advice or knowledge on this motor or rebuilds in general i would greatly appreciate it.

You will be surprised how many sources are available, including your local car-parts store, which probably has carb rebuilding kits, although theirs may not include a new float. OEM is better, in my opinion, because it is a complete kit.

Think you can get an impeller from them, as well. I don't remember.

Lots of stuff out there; it helps that the 18 is one of the most revered and durable engines ever mounted on a boat, and the design last many, many years.

Have fun, be safe.

browning1957,

NAPA STORES sell EVERY part for the 1955-1970 OMC OBs, except the exterior castings/sheet metal, under the SIERRA brand. = The NAPA stores around here carry most of the "popular parts" in-stock & will quickly get the others shipped-in.

NO, I don't work for NAPA/SIERRA but I surely buy a considerable amount of "pieces" from them to fix my "rusted, greasy, junk" (as my favorite tomboy calls my "antique motors" = LOL.)

yours, satx
OMC fan & "OB tinkerer"

Thanks for all the advice. I am hoping to have the motor up and running before I deploy again in Feb so I have a lot of work to do. Also sorry for the spelling I tried to write the first post from a cell phone lol.

There is a "thread chaser" that is shaped kind of like a square file. You can try this if the flywheel is still in place. If it has been removed then use the proper die.
Normally there is only one reason for those threads to be damaged.....and that is by a hammer. Certainly hope not. Flywheel removal is best done with a proper puller.
As far as parts go. Yes, your local auto parts store can be a source but the OEM parts and kits are of higher quality and more complete, specially the carb kit. Well worth the money. The Sierra points never seem to line up and the Sierra carb kits are severely lacking.
Am betting the powerhead does not need a rebuild unless some idiot ran it on 50:1.
As far as seals go the gearcase may need to be re-sealed. The usual culprit there is the shift shaft seal.
Make sure that engine is never run on less than a 24:1 fuel/oil ratio. The 50:1 engines did not start until 1964. And, no, the oil is not that much better no matter what Bubba or Billy Bob tells you.
Those engines are fantastic runners. Very powerful and super smooth. Great find!

Pappy,

Fyi, the oil of 2014 is MUCH better quality than that oil of my childhood in the 1950s. BUT that does NOT mean that you need less of it ; instead, it means that your OB will last longer & NOT wear out. - I run 20-1 "mix" in my "using Big Twins" & that much oil does NOT "foul the plugs". = I pre-mix all my 2-cycle gas in 10 gallon cans & buy 2-cycle oil in gallon jugs.
("Fouling plugs" is another thing that JoeBob & Bubba are WRONG about.)

Otoh, I find SIERRA parts perfectly suitable for 1955-70 Big Twins. I simply don't think that paying OEM prices is worth the difference in $$$$$. - Obviously, that's an individual's decision.

IF a person is buying their first & FOREVER OB motor, you could do far worse than a post-1965 40HP OMC.
(My cousin, who is a commercial trot-liner in south LA, is still running 7/365 the pair of 1966 OMC 40HP outboards that he bought as "leftovers" in 1968.- NO "sport" fisherman will ever equal the number of hours that Randy puts on an OB in a year.)

justmy opinion, satx

Yep.....you're preaching to the choir on the oil as far as I am concerned!

Pappy,

Given your knowledge, I would NOT be surprised to find out that you also "use too much oil" in your BigTwin.

Fwiw, I regard a restored BigTwin as "a significant investment", considering the current cost of refurbishing/rebuilding, correct paint, new decals, etc. - Therefore I want my OB to last the rest of my life and "be a disbursal problem to" my daughter/executrix after I'm long gone.

yours, satx

I have another Big Twin on its way from Minnesota as we speak. The one in my sig pic was sold last Fall.
May also be picking up a short shaft 1960 V-4 75hp Johnson from Tenn.
Of course both will be run on too much oil..................

I like to run too much oil myself. I've heard it can reduce lifetime and affect performance though :wink: .

SumDumGuy,

"I heard" all sorts of utter foolishness about OB motors (and about LOTS of other subjects) over the last nearly 7 decades. - Truthfully, I do NOT believe that "too much oil" (within reason. 2-cycle motors won't run on oil, as they are GASOLINE-fueled engines.) will affect their longevity/performance at anything near 20/1 fuel/oil mixes.

Fwiw, most any activity, engaged in to ridiculous excess by persons (including drinking too much water), can cause "problems".

just my OPINION, satx

I'm not Billy Bob.

I did check every spec and part number enough to verify two things:
(1) 1964 and later OMC engines used essentially all the same parts, torques, gaskets, and clearances of the 1963 and earlier.
(2) In 1964 the OMC Factory changed the fuel/oil mixtures...not me.(or BillyBob). The factory didn't change much else.

That being said, I base all fuel mix for my two strokes on 50:1(2%) being careful always to use quality recommended types of oil.
My saws all run Stihl oil. Outboards all are run on Mercury PremiumPlus or BRP semi synthetic. When Pennzoil is on sale that's great because I believe they manufacture oil for the big engine makers. It's been clearly marked PremiumPlus in past years.

Oils for air-cooled engines are formulated differently than oils for water-cooled engines.

I will richen the fuel/mix if:
Running full throttle for extended periods.
Running a plain bearing outboard(3,5.5,6,7.5hp OMC)
Running a new powerhead.
Running anything for the 1st time.

It is my understanding that:
Too much oil has the effect of reducing octane.
Too much oil increases the combustion temperature(burns hot).
Too much oil can reduce the fuels cooling effect on the air/fuel charge.
Too much oil reduces the amount of gasoline available for making power.
Too much oil leans the air/fuel mixture.
Too much oil promotes carbon buildup(sticking rings, etc).

Oil is necessary for lubrication, that's all. Engines won't run on pure oil, they run best on pure gasoline...but not for long; oil IS needed. The experienced engineers who build and test these engines, for a living, have determined, through years of practical experience, what mixes work and what mixes don't. We all bought their engines because they built them so well. Following their recommendations on the oil makes sense.

Everyone has their own preferences on how to mix oil and gas. After doing it for 40 years without ever having any lube related failures. These are the guidelines I use.

Again, 2c worth.

Boat2Fast,

You really should "check your data sources", as your info above is quite WRONG.
1. The BigTwins of 1955-60 are based on a power-head design from 1951 that started out as a 25HP, which was later "bored out" to make a 30 HP in 1956 & then a 35 HP outboard for years 1957-59.
2. In 1960 & 1961, that same block was bored out once more to make a 40 HP outboard & that modification was "the blow that killed Papa". - the 60 & 61 model 40s, imVho, are JUNK & were JUNK when they were new. =====> OMC replaced MANY of those OB as they often "broke down" or "blew up" before the warranty expired.
3. In early 1961, OMC completely redesigned the BigTwins, beefing them up, in every respect. = That 1962 & later 40 HP is one of the toughest, most over-engineered & "longest lived" (with even minimal care) OB ever built, for their size/power.= In nearly 50 years, I've never seen a 1962 & later BigTwin "worn out in use", though I've seen some "abused to death".

yours, satx

Boat2Fast - Glad you took the bait ! I love a good chance to challenge the thought processes of the few who are willing to learn! I by no means make that statement in a cocky manner!
I will stand by my Bubba and Billy Bob comments. I have a feeling you will as well if you are willing to get into this stuff below.

Now....at this point, since you seem to have an avid interest in two strokes, look up a fellow by the name of Gordon Jennings.
He is/was pretty much known as the Godfather of 2-stroke performance technology. He is the guy who wrote the books on this stuff. He is also the guy who utilized his engineering talents and science to back up his writings. Much of his two-stroke work was done in the air-cooled motorcycle world but what he learned and wrote about crosses over seamlessly into our marine world as well. Our engines have it made compared to the Hell a 2-stroke air-cooled bike engine goes through.
Any good tuner whether it be marine or on wheels will be familiar with his work.
He wrote an awesome two-stroke tuners handbook......good place to start.
When you look him up and start reading about him let me know and I will then take you to the next step on oil ratios.

The one statement about the engineer's recommendations on production engines isn't very valid. Oil ratios in production engines were at best a compromise between what Engineering wanted and what Marketing thought they needed to sell more engines. Sad but true. If you get into the stuff above then this statement will make more sense to you.

https://www.amrca.com/tech/tuners.pdf