HD 25 Carb percolting

[Buccaneer]

Wasn’t there something in the manual about the early HD carbs
percolating, and the remedy was to put a wire / rod in
the one passage to restrict flow?

Prepare to be boarded!

[garry-in-michigan]

Johnson suggests adding a pin to this passage . . . 😕

[shane-r13]

So i got a new impellor for my HD25 and there is a visible size difference between old and new. Doesn’t help. Still can hear fuel bubbling in carb when i place my ear next to it. Only runs for a but then dies. Water is coming out of the misting ports but whos to say its enough. I’m going to assume its not because i can hear the fuel boiling. I’ve blown out the passages with air and it comes in and out of passages fine. Whats my next step? tear down of bottom end and then remove head as well? I’m at a lose on this little farter.

[chacha53]

A new one is on the way. Thanks!

[chacha53]

Well, I installed the new grommet at the base of the water tube. Put everything back together with the new pump. Started it, no mist of water coming from the two exhaust ports in the midsection. Carb heated up. Soon it was too hot to touch so I shut it down before the gas could start boiling.
I restarted it and while it was running I removed the drain screw at the base of the head. The water that dribbled out was initially hot then it turned cool. My guess is that the hot water was draining back down from the head and out the drain. Once drained, only the cool water being pumped from the test tank came up the tube and out the drain. So the water is reaching the head, but apparently not circulating around the head and out with the exhaust. Just not enough water pressure? I’m about to throw in the towel!

[stanley]

Have you tried it without the prop on it?

[chacha53]

No, I haven’t. What’s your thought?

[stanley]

No real thought,just reducing variables.If it runs hot in the barrel with no prop,then you know the pump is not sucking air do to excess turbulence or that the pump is inefficient under load.

[chacha53]

Good points. I’ll take the prop off and try
it. Probably tomorrow. Thanks!

[chacha53]

I removed the propeller and ran it. Still no water mist coming from the exhaust ports. I removed the drain screw from the base of the head again, still just a dribble of water coming out. I’m stumped.
It starts right up and runs great. A nice little motor, just refuses to pump enough water.

[Author]

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