1976 Johnson 55hp no water jet

[darrenr]

Hi I have a 1976 55hp Evinrude that has just been rebuilt, rings ,bearings, all gaskets replaced. Compression is 150/150. It was pumping water fine then I noticed it had stopped. I replaced the impellor but still did'nt pump water. I was told the head gasket might of gone so I checked compression again still 150/150. I am now lost to what to do next. Please can you help?

 

[HighTrim]

Re: 1976 Johnson 55hp no water jet

Was the old impeller damaged/broken? Did you flush the cooling circuit while the lower unit was down? Is the intake free of debris? Did you line up the water line with the grommet properly? This is a common problem.

 

[darrenr]

Re: 1976 Johnson 55hp no water jet

Hi, Impellor was perfect but I fitted a new one just in case. Didn't flush as I thought because its never been used except for in a barrel of clean water it could'nt be blocked. When impeller was replaced it shot water for about 5 seconds then stopped. I took my time re-fitting lower unit and pretty confident that I lined it up.

 

[HighTrim]

Re: 1976 Johnson 55hp no water jet

Strange, if it was shooting water should be ok.

Was it OEM impeller or aftermarket?

 

[darrenr]

Re: 1976 Johnson 55hp no water jet

OEM. I was thinking maybe thermostat or broken exhaust gasket. What do you think?

 

[Captmills]

Re: 1976 Johnson 55hp no water jet

doesn't sound like it had time to be the thermostat, more likely to be a clog in the line if it only ran water for 5 seconds

 

[darrenr]

Re: 1976 Johnson 55hp no water jet

Can u tell me how I flush the cooling system if I remove the lower unit?

 

[HighTrim]

Re: 1976 Johnson 55hp no water jet

No neither of those would affect the tell tale. Even with a stuck t stat you would still show flow from the tell tale.

Drop the gearcase, then run compressed air or water up the water line, does it flow?

While the gearcase is down, ensure the key is still in the impeller, and the impeller did not get damaged. Also ensure that the water line does not get pinched with the grommet on top of the impeller housing.

 

[darrenr]

Re: 1976 Johnson 55hp no water jet

I removed gearcase last weekend. Attached garden hose up water line and turned on. Everything appeared to be fine. Water came from all the places it shold have. I then checked impellor key, impellor etc all looked ok. Put it all back together and fired engine. Water was shoting from jet hole perfectly. I can only think that the hose pipe must of flushed the blockage. Thanks for all help and I hope it works when I take it out on the water next month. Darren