Overheat horn on 77 johnson 115

[whitejamie99]

On my first trip out with my boat, it fired up great and idled fine and performed perfect. I idled out past the no wake zone and then hit it hard for about 5 minutes. I came back to the dock to pick up the wife and before we got out of the no wake zone the hot horn started blaring. I brought it back to the dock and let it sit. When I would turn on the key the horn would still sound. Finally after 20-30 minutes, the horn wouldn't sound and it started. I only drove it long enough to get it on the trailer.<br /><br />Am I looking a water pump repair. I dont know the shape but the water seemed to be moving through the system. Also I've heard about t-stats. Where are they located and are they easy to change. I cant find any info in the Seloc manual that helps me.<br /><br />Jamie

 

[Walker]

Re: Overheat horn on 77 johnson 115

Probably needs an impellor and thermostats both. The reason it didn't overheat while running higher rpms is the bypass valves are apparently working properly. <br />Look at the back of your motor. See the 2 3/4" hoses on either side down at the bottom of your powerhead. Now see the block that they both are clamped to. That block holds the thermostats and the bypass valves. Three 7/16" bolts hold it on. Almost takes 3 hand to put it back together too after you replace the thermostats.

 

[whitejamie99]

Re: Overheat horn on 77 johnson 115

Thanks Walker. I will replace all. Will post back with the results.

 

[Rocketdeerdog]

Re: Overheat horn on 77 johnson 115

I know this is a little off the original topic but i have a 1998 115 Im replacing the thermostats in with the same setup and am having trouble getting it back together. I only removed the thermostat housing when i was disassembling it and am having trouble with the close quarters now that i am putting it back together. Any tips or do i need to remove some additional parts to get it back together. Getting the pressure relief spring back in is the hardest part in such a tight area.<br />Thanks,<br />Randall

 

[Walker]

Re: Overheat horn on 77 johnson 115

Can't you split the cowling pan on that 1998??

 

[Rocketdeerdog]

Re: Overheat horn on 77 johnson 115

Yes. It can be removed in two pieces but i dont think that will help alot.

 

[Walker]

Re: Overheat horn on 77 johnson 115

I don't understand the "tight quarters" part.<br />Are your thermostats up on the heads or down at the back of the motor

 

[Rocketdeerdog]

Re: Overheat horn on 77 johnson 115

Yes, In the back center and very bottom of the motor. theres not much room there. it was hard enough to get it off.

 

[ledgefinder]

Re: Overheat horn on 77 johnson 115

Jamie- <br /><br />I think just one thermostat & one venostat in the 1977. It might be just the impeller, also. One way to check is to pull either of the two hoses that go from the heads to the thermostat block, then start the motor (in the water). If you get decent flow, then your thermostat or venostat is stuck; if no flow, then the water pump isn't working.<br /><br />Has the motor been run in salt a lot? If so, don't be surprised if you have no thermostat at all. Not considered to be the best practice, as the motor runs too cold, idles worse, and wears quicker. However, there are experienced mechanics around who'll pull them on an older saltwater V4, to prevent the catastrophic results of a thermostat sticking closed. It is such a bear to get the thermostat housing apart on an old saltwater 1973-77 V4 - and get it back together again right - that you may want to just leave it that way.

 

[Solittle]

Re: Overheat horn on 77 johnson 115

I have a pair of 1987s. When I replaced mine I used a couple of rubber bands to hold the stuff together. When things got where they were supposed to go I snipped the rubber bands.

 

[Rocketdeerdog]

Re: Overheat horn on 77 johnson 115

thanks