HD 25 Carb percolting

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Buccaneer
Posts: 3254
Joined: Mon Mar 09, 2015 9:34 pm

Re: HD 25 Carb percolting

Postby Buccaneer » Tue Aug 07, 2018 9:06 pm

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?

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Garry in Tampa
Posts: 2861
Joined: Mon Mar 09, 2015 2:32 pm
Location: Florida

Re: HD 25 Carb percolting

Postby Garry in Tampa » Wed Aug 08, 2018 3:56 am

Johnson suggests adding a pin to this passage . . . :?
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Shane.R13
Posts: 146
Joined: Tue Jan 30, 2018 10:03 pm

Re: HD 25 Carb percolting

Postby Shane.R13 » Thu Aug 16, 2018 2:51 pm

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.
1946-49 Johnson TD-20 5HP
1946-51 Johnson HD-25 2.5HP
1959 Evinrude 18hp Golden Jubilee
1978 Artic Spirit(Suzuki) 20HP
1975 Evinrude Mate 2HP
1977 Johnson 25HP
1980 Mercury 18HP
1987 Mariner 9.9HP

and growing hopefully

Chacha53
Posts: 30
Joined: Thu Aug 17, 2017 5:14 am

Re: HD 25 Carb percolting

Postby Chacha53 » Sat Aug 25, 2018 9:56 am

A new one is on the way. Thanks!
Chattanooga, TN

Chacha53
Posts: 30
Joined: Thu Aug 17, 2017 5:14 am

Re: HD 25 Carb percolting

Postby Chacha53 » Thu Aug 30, 2018 10:30 am

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!
Chattanooga, TN

Stanley
Posts: 308
Joined: Tue Mar 10, 2015 9:21 pm

Re: HD 25 Carb percolting

Postby Stanley » Thu Aug 30, 2018 10:46 am

Have you tried it without the prop on it?

Chacha53
Posts: 30
Joined: Thu Aug 17, 2017 5:14 am

Re: HD 25 Carb percolting

Postby Chacha53 » Thu Aug 30, 2018 5:01 pm

No, I haven’t. What’s your thought?
Chattanooga, TN

Stanley
Posts: 308
Joined: Tue Mar 10, 2015 9:21 pm

Re: HD 25 Carb percolting

Postby Stanley » Thu Aug 30, 2018 6:51 pm

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
Posts: 30
Joined: Thu Aug 17, 2017 5:14 am

Re: HD 25 Carb percolting

Postby Chacha53 » Thu Aug 30, 2018 7:02 pm

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

Chacha53
Posts: 30
Joined: Thu Aug 17, 2017 5:14 am

Re: HD 25 Carb percolting

Postby Chacha53 » Fri Aug 31, 2018 5:30 pm

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.
Chattanooga, TN


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