1989 Johnson 90hp v4 Water Problem

[Marinewithaboat]

A couple of weeks back we took the boat out and during our trip noticed the tell tale stream was really weak as we started to head back in fear of overheating the engine it shot strong again and stayed strong. Decided to keep fishing. Ran the boat a few days later and everything seemed normal. Yesterday went to run the engine on the muffs to get ready for a fishing trip today and everything went wrong. The idle was really rough and it eventually died. Open the cowl to find a really hot engine block. Decided to give it a few and run it again this time with the cowl off. As it was running I noticed water around the base of the block. The tell tale stream was still strong but the engine was really hot. I also noticed a wierd hot water then really cold water coming from the tell tale. Also more water began appearing around the block. Engine died again, one last started provided an engine that only runs at fast idle.

I'm not the best mechanic in the world so the debate is due I take it to a shop and have it fixed or does it sound like something I can do myself. Any help would be greatly appreciated.

 

[rndn]

Re: 1989 Johnson 90hp v4 Water Problem

Without knowing where the water is coming from around the base of the block, no one can help. For sure it may need an impeller and or thermostat(s). If you don't feel good about working on it yourself and don't have a manual, then take it to a reputable service place and have them look it over for you. Trial and error and running it hotter than it's supposed to can only increase the cost of future repairs including a repacement powerhead. Read $$$$.

 

[rndn]

Re: 1989 Johnson 90hp v4 Water Problem

By the way, thank you for what you and your buddies do/did so we can all enjoy fishing and boating in our great country. I was in the army, you know the harder tougher armed force, but we still respected the Marines. Hah hah, just joking.

 

[Marinewithaboat]

Re: 1989 Johnson 90hp v4 Water Problem

So I pulled off the thermostats today and ran the motor for a second and the problem was alleviated. Is it safe to say it was faulty thermostats?

 

[wavrider]

Re: 1989 Johnson 90hp v4 Water Problem

First suggestion, get a manual they are worth there weight in gold, or sort of like marine blood stripes (retired Navy here, served with some MAG outfits)

If you pulled the thermostats and they were bad could have been stuck thermostats, and leaking gaskets at the thermostats.

Do a compression check to see how the internals are doing and that will be the starting point for maintenance.

If compression is good then gaskets are good usually.

Definately replace impellar,inspect water pump housings n seals and replace your thermostats.

Then see how the engine runs from there. I am no expert and I probaly missed something but I am sure someone will fill in the blanks I left out. Enjoy,WAV.

 

[emdsapmgr]

Re: 1989 Johnson 90hp v4 Water Problem

Before you go further, I'd check the compression to be sure the power head did not suffer during the overheat. When you have the thermostat apart, make sure the two small holes in the valve body are open. Each hole feeds water to each thermostat and if plugged, that side of the block will overheat. Probably a good idea to replace both thermostats anyway. Check the nylon pressure relief valves to be sure the overheat did not deform them. If the powerhead base gasket is faulty, it can leak water inside the lower cowl.

 

[kenmyfam]

Re: 1989 Johnson 90hp v4 Water Problem

Compression check for sure. Good check for general motor health.