1959 Big Twin 35 Cooling

[jeffy104]

My 35 big twin has been sitting for 6 years in the shop (heated) and I got it out and ran it on my '47 pennyan hatchetboat in Canada Lake yesterday (in a huge thunderstorm) and It started up on the 3rd pull. Sweet! There was a good amount of steam coming from the exhaust along with the water....it was cool out there at the launch with the rain and all.... Motor did not seem to run the way it should so I figure points need checking....or maybe high and low speed knobs.....just wasn't smooth, you know. Anyway, I have had the motor for about 15 years and never changed the impeller on the pump. I will put up a picture of it running with the steam right after I get the points checked out. Time for an impeller change?
Conservative in the Adirondacks.

 

[CATransplant]

Re: 1959 Big Twin 35 Cooling

Long past time for an impeller change. Do that before you do anything else. If you're lucky, you didn't damage the engine by overheating it.

15 years? Most Big Twin owners change impellers every couple of years, as a preventive maintenance job.

 

[tashasdaddy]

Re: 1959 Big Twin 35 Cooling

change the impeller immediately. i would also do the tstat, easy on that motor, 2 bolts. do not spray anything into the carb, but premixed gas and oil. the second set of instructions should help you get it running correctly, as long as the carbs are clean, and you have proper spark and compression.
http://forums.iboats.com/showthread.php?t=167352
also the leg of that motor must be submerge 1/2 way up the leg if testing in a barrel, and keep the hose running.

 

[jeffy104]

Re: 1959 Big Twin 35 Cooling

Well, found out from the owners manual that a good cloud of vapor from the cooling water is normal when temps are below 70. Plenty of cooling water comming out the back. So for good measure, I took the tstat out and it seems fine. Now a new problem......Can not get it to idle. Tried everything with the carb. Even re-machined the low speed jet stud because it had a notch toward the pointed end that I don't think was supposed to be there. Runs great at 1/2 throttle or better.....very smooth and tons of power but just dies when I throttle back. Now, it is running on one cylinder so points and condensers are next. Checked the points....cleaned and gapped at .020" Got new plugs. Gapped at .030. If that doesn't getit, I'll change out the coils I suppose. Has always been very reliable and this is the first time I have had trouble with it. I will probably be selling this year and looking for a bigger boat. The '47 Penyann with motor and trailer should bring 1000.00? Any ideas? jeffy104@aol.com 315-868-6515

 

[mikesea]

Re: 1959 Big Twin 35 Cooling

You are a lucky man.Its just a matter of time that the impeller disinergrates and plugs things up from its dried out rubber vanes.I'm suprised the carb is not giving more grief.You might want to insure the mag.plate under the flywheel is rotating freely.You may be losing the timing when throttling,Also be sure your kill button leads arent grounding from dried up insulation

 

[F_R]

Re: 1959 Big Twin 35 Cooling

So when you were in there looking at the points, how did the coils look? It is a rare '59 OMC motor that doesn't have bad coils if they are still the originals.

 

[jeffy104]

Re: 1959 Big Twin 35 Cooling

So....the coils look good....changed the points and runs good on both cylinders.
I think there is something that i am missing in the carb....I am looking for another one! Anyone know where i should look? Thanks for your answers guys....Jeff

 

[F_R]

Re: 1959 Big Twin 35 Cooling

But you said it runs on one cylinder. A carburetor won't make it run on one because it feed both.

However, a bad fuel pump diaphragm will make it run on one. Remove the pulse line and squeeze the squeezer bulb. If gas squirts out the hose fitting, the diaphragm is holed.

Could be a spark plug wire arcing through also. Especially where they are clamped to the armature plate.