help 77 johnson 55 hp changed water impeller and now engine don't run

[tloehner]

changed water pump impeller and took it out for a test run. when i was out my overheat alarm went off. so i brought the boat back in and dropped the lower unit. it smoked a little bit. the water tube wasn't in correctly. put it back together correctly.took boat for a ride. it work fine for about 10 minutes then it gradually die. try to get it started again and nothing drained battery trying.<br /><br /> next day and my spare battery, tried to start it thinking i flooded it the day before and nothing. <br />couldn't get it to turn over. DEAD BATTERY 10 minutes later. took the fuel i had and dump it and put fresh fuel in. tried to drain as much old gas from motor. <br /><br />next day go with two batterys pull plugs didnt look bad, got it to start for about 2 minutes then nothing after that. DEAD DEAD when it ran for the two minutes i tried to go full throttle and it seemed like it was at half power. Help help<br /><br />sorry for beening so long, but wanted you to have background to work with. what should compession be at, want to test that tommorow. thank in advance

 

[DJ]

Re: help 77 johnson 55 hp changed water impeller and now engine don't run

tomsboat,<br /><br />I do not know how hot it got, but hopefully, you didn't cook a cylinder.<br /><br />Anyway, do these things.<br /><br />1. Check for spark on all cylinders.<br /><br />2. Compression should be around 100 psi. Most importantly, the cylinders should be with 10% of each other. (Remember-check the compression with the ignition disabled and the throttle open.<br /><br />Get back to us and let us know what you find.

 

[tloehner]

Re: help 77 johnson 55 hp changed water impeller and now engine don't run

thanks will pull boat in morning and work on it.

 

[tloehner]

Re: help 77 johnson 55 hp changed water impeller and now engine don't run

well took a compression test. one read 150 and the other read 50 .. so i took off the head and the head gasket was blown.. the cylinder was scored a tiny bit, two little fine grooves on top and one little fine groove on bottom. should i put a new head gasket on a do another compression check. what are my options ???<br /><br />thanks in advance.

 

[OBJ]

Re: help 77 johnson 55 hp changed water impeller and now engine don't run

Hi Tom, I think the compression test and condition of the cylinder is telling you all you need to know. Time to rebuild or look for another engine. With a compression that low in one cylinder, not much more you can do with it.