TC-W3 ratio

[Cadillac-ack-ack]

I know this must have been gone over a bunch of times and someone asked and received an answer to this exact question some 230 forum pages back.It was in reference to a '65 40 HP though and although my '62 Lark is, I believe, an identical motor I wanted a fresh perspective. Is the ratio of TC-W3 24:1 as original specs imply, or is 50:1 correct? Something in between? How about 1st tank ratio for this rebuilt engine? The motor's still not ready to go (neither is the lake with at least 2'+ of ice still), just projecting ahead to summer. - Pete

 

[F_R]

You'll never get people to agree on that question. My opinion is as you suspect, there is no significant difference between pre-1964 and later powerheads. So, 50:1 is fine for your '62. Now, let the firing squad begin.

Yes. 24:1 for the first tankful, for break-in.

 

[racerone]

Lubrication and what happens to the oil after it is mixed with the gas is not well understood.----Yes you will get many different opinions !

 

[Scott Danforth]

oooh another oil thread

 

[Chris1956]

The original spec for Johnnyrudes was 24::1 for motors manufactured before 1964. Most of the pre-1964 motors had bushings, which require the 24::1 fuel mix.

However, some of the motors manufactured before 1964 had roller and needle bearings, and were fine to run at 50::1.

I am not sure which motors have the change to roller and needle bearings, and what year they changed over. Some on this site know for sure, as they have worked on them.

 

[racerone]

The 1949 QD 10 had some needle bearings.-------Some just do not understand how oil " works " in a 2 stroke.

 

[Cadillac-ack-ack]

The original spec for Johnnyrudes was 24::1 for motors manufactured before 1964. Most of the pre-1964 motors had bushings, which require the 24::1 fuel mix.

However, some of the motors manufactured before 1964 had roller and needle bearings, and were fine to run at 50::1.

.

I can't speak of the lower HP motors but my '62 40 has needles throughout.

I know what you mean Scott, In other (car and bike) forums I have joined and contributed to "oil" is like politics. Especially when recommending "the best (you're an idiot if you don't use this stuff) brand". Not my wishes here, only looking for ratio info. I'm curious as to why only 50:1 or twice as much 24:1 seems to be the only alternatives. Why is, say, 32:1 or 40:1 never mentioned as an alternative for older units? - Pete

 

[Scott Danforth]

I hear you on multiple engines with multiple ratios

i run my old bushed gale at 24:1, my chain saw and other out-door power equipment at 32:1 and my moped that takes pre-mix gets 32:1 vs 40:1. my new to me 20hp is 50:1. for testing it will get run at 32:1 as I only have 1 portable can for mix, and two boat cans.

Made the mistake of running my old Mac10 on 40:1 vs 24:1 when cutting up a palm tree.....it lasted about 1/2 hour before the piston, bearings, and jug became one with a loud "THWACK"

a bit more lube doesnt hurt, however a bit less than needed ends in failure....

 

[racerone]

???----The 50:1 was a board room decision and not done with results from laboratory tests !!!----It seems the general public thinks that a motor that can run on 50:1 is a better motor than a 24:1 motor.-----So to generate sales they decided to go 50:1 like the competition.----At that time it was a battle between 2 companies !----A far cry from the world of global marketing of today !!

 

[Cadillac-ack-ack]

???----The 50:1 was a board room decision and not done with results from laboratory tests
--It seems the general public thinks that a motor that can run on 50:1 is a better motor than a 24:1 motor.-----

!

I was under the impression it was the "new" TC-W3 oil along with outboard development that allowed 50:1 to work. I mentioned in an earlier thread I have three quart cans of Valvoline "outboard motor oil". No fancy- smancy nomenclature anywhere but a list of things it worked with from "motor bikes" to "chainsaws" to "power mowers" and "other two-cycle gasoline engines". Can's also got some silhouettes of equipment and a drawing of two motor boats. Back in the day we dumped one of these cans into the 6 gal fuel tank, filled 'er up and went skiing. I have since thought that TC-W3 rated oil was simply better than this so 50:1 "could" be used. Think I could break the motor in on this @ 24:1?

 

[Chris1956]

Cadillac, a 50::1 fuel mix was used on sixties Mercs and Johnnyrudes, well before the invention of TCW rated oil.

 

[racerone]

Most pre 1964 had " bushings " ????----Many folks do not know the facts.----A 1962 model 10 hp has roller / needle bearings.-----The wrist pin needle bearing on the 10 is the same as what was on the wrist pins of a 100 hp V-4 of the 1960's !!

 

[Chris1956]

Ok Racer, when were which Johnnyrudes equipped with all roller, needle and ball bearings on the mains, crankpin and wristpin bearing journals? I presume the changeover from some bushings to all bearings occurred at different times for different HP models. No?

 

[jimmbo]

The 1957 and newer 35hp and 40, as well as the all the V4s were roller and needle bearing engines and could live on the 50:1 mix.
The 1964 5 1/2hp still had a bushing as the lower crankshaft bearing, but OMC figured there would be enough oil puddling there to keep it well oiled so 50:1 was the spec for it.
I'm not going to include any other engines

 

[F_R]

Ok Racer, when were which Johnnyrudes equipped with all roller, needle and ball bearings on the mains, crankpin and wristpin bearing journals? I presume the changeover from some bushings to all bearings occurred at different times for different HP models. No?

You presume correctly.

 

[Cadillac-ack-ack]

So the consensus seems to be after a 24:1 tank full through the fresh engine, 50:1 is correct. Yes?

 

[jimmbo]

The owners manuals for the post 63 OMC motors in the 60s said 24:1 for the first 10 hrs of operation

 

[Yoslick]

I dont mind a little smoke, keeps them Minnesota Loons (Mosquitos) away.... 32:1

 

[todd281]

My understanding on the subject is that while there were some changes made in the motors, the big changes were in the oil. We all know that running your outboard on a lean mix may cost you a power-head and a paddle to shore. The down side of to rich,,, maybe a plug [ although I have not fouled one yet] performance.. [I have not seen any difference] Cost of the extra oil,, [Yup] some extra smoke on the water,, . So the question becomes , Do the benefits of running a lean mix , outweigh the possible costs? As far as running on a different mix , say 30:1 or 40:1 the answers are the same,, Do you feel lucky?

 

[racerone]

Todd281-----What exactly happens to the oil once it goes through the carburetor and into the crankcase.?