Big twin 30

[Animal1]

Hi guys.This is my first post on iboats.
I just picked up a Starcraft 16 with an old(I mean really old)Outboard.I've been told by three different people that it's a 56,a57,and a 58.I don't know a lot about outboards.My plan is to use this for playing around till I can find something 40-50 yrs newer.The way I fish,and spend time on the water,I can't be out there with this motor.Anyways,I'm interested in learning anything I can about it.Thanks in advance,Bobby.

 

[bktheking]

Re: Big twin 30

What are the number on the plate if it's got one??? BTW the old motors rock, my buddy runs a 64 big twin 40, another guy pulled out last week with the exact same setup as my buddy, recognized it instantly, he's been running his 64 for 7 years and won't change it for anything. Super realiable engines, you may reconsider something newer/more complicated.

 

[Daviet]

Re: Big twin 30

You need to post model number, then someone can tell you what yeat it is.

 

[Animal1]

Re: Big twin 30

On the front of the motor,there is a serial no,on the plate.
25022-18108
It's the only number I've yet found on it.
It's a bear to (pull)start,but seems to run pretty good.Forward and reverse are both working(in a barrel)I hope to test splash in the next couple days.

 

[bktheking]

Re: Big twin 30

1956 my friend and correct me if i'm wrong fellow iboaters, the only year it was made.

 

[Daviet]

Re: Big twin 30

That makes it one of two things, a piece of junk or a collectors item. I prefer the latter.

 

[cougar1985]

Re: Big twin 30

1956 was only year of 30 hp big twin.just redid one for a guy last year,i tried hard to get him to sell it with no luck ,what a nice motor.it was very smooth and beautiful.owe well will keep trying ,lol.parts are still readly available,and their easy to work on .verify good compression first.not sure what you mean by the way you fish but i use my 18hp 1957/58 johnson all the time ,sometimes trolling for hours at a time then running miles back to the ramp.had a guy with a e-tec compliment me on how smooth and well it ran so dont give up or dismiss the old omc,s that easily.

 

[lindy46]

Re: Big twin 30

Wonderfully reliable and simple motors to work on. I have a '57 Lark (35hp) and fish 4-5 times a week all summer long with it. Never been stranded and she idles down to a nice 2mph troll for hours without fouling. I wouldn't trade it for a newer, expensive, and complicated motor with all the fancy electronics.

 

[tmcalavy]

Re: Big twin 30

The Big Twins started out as 25 hp in the early 50's, went to 30 hp in 56, and 35 hp in 57 and 58....then to 40 hp after that. Really sweet motors...good runners, easy to maintain, quick and powerful, and easy to swap/move around, too. Even if you upgrade to a newer motor, I'd keep that one as backup power...unless it is damaged inside in some way. Be sure you run it at 24:1 or 32:1 and not 50:1.

 

[Animal1]

Re: Big twin 30

Thanks for the replies everyone.I've got a question about the mix.On the inside of the engine cover,within the starting and operating instructions,it says to use sae-30,at 1 quart per tank of gas.ora half pint per gallon of gas.Huh?I'm guessing that two stroke oil wasn't very good back then?Should I disregard this,and use 2 cycle?If so,is it a half pint per gallon?Thanks,Bobby.

 

[coolguy147]

Re: Big twin 30

24:1 oil and fuel mixture tcw-3 rated 2 stroke oil. synthetic will smoke less

 

[samo_ott]

Re: Big twin 30

The Big Twins started out as 25 hp in the early 50's, went to 30 hp in 56, and 35 hp in 57 and 58....then to 40 hp after that. Really sweet motors...good runners, easy to maintain, quick and powerful, and easy to swap/move around, too. Even if you upgrade to a newer motor, I'd keep that one as backup power...unless it is damaged inside in some way. Be sure you run it at 24:1 or 32:1 and not 50:1.

Close... The 35hp was around in '59 also I have the J30, the E30 and a J35 and just got last week an E35. All good old engines. Hope to have em running soon also

 

[coolguy147]

Re: Big twin 30

in my link photobucket i have a 1958 johnson 35hp. super quiet model


yet it has a 1959 hood probably something happened to it but it works just fine

 

[cougar1985]

Re: Big twin 30

Close... The 35hp was around in '59 also I have the J30, the E30 and a J35 and just got last week an E35. All good old engines. Hope to have em running soon also

they only made the 30 hp for 1 year 1956 ,after that they went to 35 hp.go to old-omc .com for lots of interesting stuff on various years of omc,s.

 

[F_R]

Re: Big twin 30

Thanks for the replies everyone.I've got a question about the mix.On the inside of the engine cover,within the starting and operating instructions,it says to use sae-30,at 1 quart per tank of gas.ora half pint per gallon of gas.Huh?I'm guessing that two stroke oil wasn't very good back then?Should I disregard this,and use 2 cycle?If so,is it a half pint per gallon?Thanks,Bobby.

Back then, outboard oil was sold in 1/2 pint cans, just like now it is sold in pint cans. So, in the old days you just dumped in a can of oil and a gallon of gas.
Oh, and yeah it was also sold in quarts. Dump in a qt and fill 'er up.

 

[tmcalavy]

Re: Big twin 30

You're right Samo...couldn't quite remember when the transition year occurred.

 

[cougar1985]

Re: Big twin 30

sorry samo, i misread your post.

 

[jasper60103]

Re: Big twin 30

On the front of the motor,there is a serial no,on the plate.
25022-18108
It's the only number I've yet found on it.
It's a bear to (pull)start,but seems to run pretty good.Forward and reverse are both working(in a barrel)I hope to test splash in the next couple days.

Yes, those big twins are a hard pull. If your lake trial goes well, why not invest in an electric starter?
If your motor has teeth and a starter bracket, I bet you can pick-up a starter and solenoid cheap off ebay. I added one to my '62 28hp.

 

[Animal1]

Re: Big twin 30

Thanks again guys.I took it out for about 4 hours today.It ran well,and the boat didn't take on much,if any water.The only pproblem was that it wont idle.It has the large and small adjustment knobs on the engine cover,but according to the instruction sticker,you finetune with the small knob,once at idle.I can't stay at idle without throttle play,so I had no luck.
Can anyone point me towards an online owners manual,or a place to order a paper one?Thanks,Bobby.
ps,you guys weren't kidding about it being thirsty.

 

[bktheking]

Re: Big twin 30

All boats/motors are thirsty. Try a 24ft larson with a 5.7litre inboard, 2x10km trips and 3 days @ 20 minutes tubing=$160

We don't boat for fuel economy that's for sure.