Honda B100 cooling question

[bobhumphrey]

Hi all. I have a 1978 Honda B100 (10 horse) outboard. I just put a new thermostat and water pump in it but am concerned that, for some reason, it isn't cooling properly. When I start it, the only water that shows is coming out of a small rubber hose that vents out of the same area where the carburetor overflow vents (on the right side as you face the engine from the boat). This water comes out cool even when the head is hot to the touch. When I feel the head, it gets almost too warm to handle within about a minute of starting (I can put my hand on it but it seems pretty hot). At that point, there's no water coming out of the two little holes on the back of the engine (where most outboards seem to have water flowing).<br /><br />So, my questions are as follows: How hot should the head feel when it is at operating temp, and when, if ever, does water start flowing out those two little holes in the back? Is there a reliable way to test the engine temperature? I've been shutting it down when it gets almost too hot to touch but noticed that it seems to be running poorly right before I do. This all takes no more than a minute or so.<br /><br />By the way, I rechecked the impeller and woodruff key along with the seal on the up tube from the water pump. I have also blown air into the water passage under the thermostat and everything seems clear.<br /><br />Any help from someone experienced with these engines would be greatly appreciated.<br /><br />Thanks ahead of time,<br /><br />Bob

 

[MOTION LINE]

Re: Honda B100 cooling question

Hi, I had a overheating problem and couldn´t find anything wrong with the engine until I took it completly in pieces.<br />Found out that the coolingwater passage in the block was full of debris, remove the block turn it up side down and look at the water passages they are probably stucked.

 

[bobhumphrey]

Re: Honda B100 cooling question

That is the next step for me. Thanks for the reply.

 

[pondhopper]

Re: Honda B100 cooling question

Please let me know how it goes. I have the exact same problem and haven't been able to resolve it. <br /><br />Thanks

 

[murrayw91]

Re: Honda B100 cooling question

Bob,<br />Did you ever come to a conclusion with your B100?<br />I have the same motor with the same problem. I have good water flow but it still over heats and shuts down.<br /><br />Good fishing!<br />Murray

 

[pondhopper]

Re: Honda B100 cooling question

Hey guys, as I mentioned I had the exact same problem. I broke down and had the experts take a look at it. They should have it fixed in a week or two. I'll find out what they did to fix it and update. I have a feeling they will need to take the entire block off, as mentioned.

 

[pondhopper]

Re: Honda B100 cooling question

Well the experts took a look and couldn't figure out the problem. (Good waste of money) I took it out over the weekend and it still overheats. I checked it all over again and 8 hours later couldn't find strong evidnce of any blockage. <br /> <br />I do have a question, what does the "throttle nozzle" do. It the little piece that fits inside the nipple of the intake manafold right before the thermostat. It has a small whole that looks like it would constricts water flow. I left it out and the water flows better and cools the engine better. I'm worried I'll be screwing something else up with out the little piece. Why is there, do i need it?