1978 Johnson, neutral or drive to flush?

[KCKracker]

1978 Johnson 200 horse V6, last year to this spring it would overheat if it was idling for only a few minutes, then cool off underway. Put a new waterpump kit in it and it was fine. For an hour solid it idled perfect on testing it. Now Im trying to fish and its happening again after a new pump conf:

Q: I noticed something else, It was confirmed that my motor does not have a telltale (1978 year too early) and that it has high speed water exhaust outlets of some kind,
well,,, I noticed that water comes out of those in gear even low rpm, but not neutral, and i always use neutral at the wash station for safety, has that caused something to not get washed out right already and be salted up? ?

 

[wilde1j]

Re: 1978 Johnson, neutral or drive to flush?

Neutral or in gear makes no difference, although safer in neutral (someone could get seriously cut). Nothing gets damaged as long as the water is getting to the pump.

Should get a fine spray out of the relief ports, most cooling water exits through the prop hub and other points on the lower unit, not the two round relief ports just below the powerhead.

 

[ezeke]

Re: 1978 Johnson, neutral or drive to flush?

You will probably need to service your thermostats and replace your water deflectors to get your cooling system working properly and consistently.

 

[KCKracker]

Re: 1978 Johnson, neutral or drive to flush?

Guys thanks. I didnt think it matters. I dont get a fine spray I get a small stream or larger depending on RPM out the ports.

what are water deflectors?

 

[ezeke]

Re: 1978 Johnson, neutral or drive to flush?

You have six rubber deflectors in the cooling passages around your cylinders. They have to be replaced from time to time - requires removing the cylinder heads.

 

[KCKracker]

Re: 1978 Johnson, neutral or drive to flush?

4 years later still over heats at an idle, so, are these rubber deflectors still available?

 

[Will Bark]

Re: 1978 Johnson, neutral or drive to flush?

Most people make their own, they are nothing more than rubber hoses cut to length as you take them out.

 

[emdsapmgr]

Re: 1978 Johnson, neutral or drive to flush?

1978 was the first year for the telltale indicators. Are you sure your engine is a 78? Maybe it's a 77.

 

[KCKracker]

Re: 1978 Johnson, neutral or drive to flush?

by the tag it is and i dont have a tattle tale.

 

[emdsapmgr]

Re: 1978 Johnson, neutral or drive to flush?

Maybe a replacement powerhead. What does the model number on the top of the block indicate?

 

[KCKracker]

Re: 1978 Johnson, neutral or drive to flush?

going to pull the power heads and check this bypass hose and also make sure passages are clear, it keeps a perfect temp and has a new impeller but starts to heat up is its idling off the hose and sitting in the water for very long on a warm day. GOD i hope i dont have any bolts break

 

[KCKracker]

Re: 1978 Johnson, neutral or drive to flush?

ok so i pulled them, the passages are CRYSTAL clean, still showing off the original primer inside! i knew there was a reason ai always flush well after salt fishing. ok so passages are superb, so about these "water deflectors" are they supposed to flow water or just block it? mine are all in tact, but closed flat. i left the bottom deflector in to show.

 

[emdsapmgr]

Re: 1978 Johnson, neutral or drive to flush?

The deflectors look to have been properly placed. As positioned, they direct the water up to the next piston. That's probably not a 78 engine. The power packs are more typical of 1976/1977. It's got the older 76/77 belcrank shifter under the bottom carb. The top piston may have been replaced with a 0.20 over piston.