Honda 7.5 Overheating. Need Help!

Joined
Jun 11, 2010
Messages
3
First time poster here. And not a mechanical genius. And no service manual.

I purchased this 1983 Honda new. It's a BF75L-1501632. It has always run flawlessly with only a couple of minor repairs needed in almost 30 years. Until now.

When it start it in a garbage can full of water (as I have done many times over the years), I get a decent stream of water flowing from the "pee hole" at the back of the engine. That stream, however, only lasts about 2 minutes, then begins to sputter and spit. The dribbling water turns boiling hot and only steam starts to come out of the outlet. I turn the engine off at this point. If I let it cool down and restart it, the same thing occurs. Steady stream for a minute or two then nothing.

In the past few days I have replaced the impeller (That was fun. Not.). The old one didn't look bad, and the new one didn't change the problem.

I then removed the intake manifold to take the thermostat out of the system, and found that there was no thermostat. It must have been removed during a previous repair. The water passages in the manifold were all very clean with no clogs at all.

Water inlet screen does not appear to be dirty or blocked.

Help me! What can be causing this problem.

Thanks,
Doug
Santa Rosa, CA
 

Tronald

Seaman
Joined
Nov 9, 2009
Messages
58
Re: Honda 7.5 Overheating. Need Help!

I had a very similar situation on a 5hp Honda a couple of years back and it turned out to be the rubber grommet that runs from the coolant tube to the power head. It was totally gone. The only way for me to find it was to remove the power head (I actually found to be pretty easy) and then there was the grommet....in pieces.

Good luck!

Tronald
 
Joined
Jun 11, 2010
Messages
3
Re: Honda 7.5 Overheating. Need Help!

Tronald...thanks for the reply. I was just looking at an online exploded diagram and telling my wife that I bet it is either the upper or lower grommet that is causing the problem.

I'm SO hoping it's the lower one. I don't remember seeing it when I had the lower unit off a couple of days ago...but I wasn't looking for it at that time. Guess I'll take it all apart again this weekend.

I assume that your's was the upper grommet, correct?

Thanks again.
 

Tronald

Seaman
Joined
Nov 9, 2009
Messages
58
Re: Honda 7.5 Overheating. Need Help!

Mine was the upper grommet. You will also need the gaskets for the power head and plate as well. It's really not too bad...but, I am a licensed auto mechanic with 30 years experience and have dealt with much much more complicated devices. I find outboards are pretty easy in comparison....it's just the diagnosis that can be a bit tricky.

Best O' luck to you,

Tronald
 
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