Opinions on the 1979 140hp johnson?

[RedRodder]

I am about to aquire my next boat and I find it having an engine that I am unfamiliar with. The boat is a 1979 Tahiti, and it is running it's original 140hp johnson. I have dealt with old mercurys but never the johnsons, are they decent if maintained? Are parts still readily available? Are repairs simple? These are some of the types of questions I have going in, the motor currently runs good, I have not been able to do a comp check, but it does idle smooth. I was told to replace the waterpump every 2 years, is this neccasary? Any info and opinions would be appreciated,

Thanks, Robin

 

[emdsapmgr]

Re: Opinions on the 1979 140hp johnson?

That engine was a highly desired engine in it's day. OMC sold many thousands of these V4 crossflow type engines and they are still around today. They are strong engines. Parts are still readily available. The value on any engine depends on the maintenance which it has had over the years. A compression check and a visual check of the gear oil (check for water intrusion) are basic factors in any purchase. OMC impellers are designed well and actually last for many years. In extreme use situations, replacement every two years is good. I've seen them last for 5-6 years (or more) and still pump water. If you don't know the documented maint history and if you purchase it, I'd consider replacing the impeller and the two thermostats so that you know just where you are as the new owner.

 

[RedRodder]

Re: Opinions on the 1979 140hp johnson?

Thanks, would you recommend any particular parts source for the johnsons?

 

[mamm7215]

Re: Opinions on the 1979 140hp johnson?

iboats, boats.net, check your local yellow pages for an Evinrude dealer, they'll have Johnson parts...

 

[RedRodder]

Re: Opinions on the 1979 140hp johnson?

Cool, any conditions based issues these engines suffer from? An rpm they don't like, weather they don't like etc.?

 

[Al-53]

Re: Opinions on the 1979 140hp johnson?

Get it running good is all....Reg gas is fine....87 octane....run sea foam in the tank and a stabilizer and de carb .....

they run in any weather....rain...snow...

proper maintainence is your friend....

 

[mamm7215]

Re: Opinions on the 1979 140hp johnson?

Actually from my reading of these Johnson forums, the overwhelmingly most common issue seems to be issues around not idling in the water. I always see "it runs fine above "x" rpm but only idles a bit then dies..." Clean carbs/fuel/lines is critical, as is proper syncing/timing. Same I'm sure for most outboards. Otherwise rock solid.

 

[emdsapmgr]

Re: Opinions on the 1979 140hp johnson?

These crossflow engines always seem to run better when you periodically clean their combustion chambers and rings of accumulated carbon. Bombardier makes a product called Engine Tuner which used annually-keeps the inside of the engine clean and idling well.

 

[RedRodder]

Re: Opinions on the 1979 140hp johnson?

sounds good, can't wait to get this puppy out on the water!