78 70hp evenrude cooked

[wasa]

giday great site guys. overheated engine on boxing day blocked inlet. replaced impeller and flushed through. telltale now flowes for short time then stops. could this be a suction prob . cant get a new pump body till the 6th

 

[HybridMX6]

Re: 78 70hp evenrude cooked

How long is a short time? Like 5 seconds or like a minute or two?

 

[wasa]

Re: 78 70hp evenrude cooked

sorry mate about 1 minuet

 

[James R]

Re: 78 70hp evenrude cooked

If the overheat was as a result of impeller failure there is a good chance that there is a blockage caused by pieces of the old impeller. The blockage may be only the telltale but I would pull the lower and back flush through the tell tale then remove the thermostat and back flush through there.If you are lucky you wont have any bits trapped in the waterways in the head and block.

 

[HybridMX6]

Re: 78 70hp evenrude cooked

I am sure others will have more advice for you, but my suggestion at this time would be to drop the lower unit again, remove the thermostat cover and thermostat, and stick a garden hose in the hole and back flush the system. Something could have gotten lodged up in there, and also replace the thermostat while you are in there. It sort of sounds like something is wrong with it if it flows at first but then stops, either that or there is something causing a blockage.

 

[iwombat]

Re: 78 70hp evenrude cooked

Is this on the hose, or in the water? If on the hose, make sure you've got lots of water pressure going in. You might also want to check your spark plugs for anything that looks steam cleaned. There's a decent chance you've got a head gasket blown and you're pressurizing the water jacket enough to cancel out the impeller. You getting any air or steam out the tell-tale?

 

[wasa]

Re: 78 70hp evenrude cooked powerhead?

Re: 78 70hp evenrude cooked powerhead?

yes i am getting steam. seems like head gasket is cracked. i have a 77 70hp johnson with a good powerhead i can swap over the only problem i see is i can not find a tell tale outlet any sugestions

 

[tashasdaddy]

Re: 78 70hp evenrude cooked powerhead?

Re: 78 70hp evenrude cooked powerhead?

why swap power head until you are sure what is wrong, could just be an easy fix, like a $20 head gasket. pull the cylinder head, and see,

 

[wasa]

Re: 78 70hp evenrude cooked

thnx will investigate further tomorrow happy new year to all

 

[KLINDWW]

Re: 78 70hp evenrude cooked

As far as the tattle tail outlet, the 1977 Johnson?s did not have them yet. I think it was 1979 when they started putting them on the engines. If you would like to install one there is a great thread in the FAQ section on how to install one.

 

[tashasdaddy]

Re: 78 70hp evenrude cooked

while you have the head off would be a great time to install a tale tell.

http://forums.iboats.com/showthread.php?t=222677