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g26 pum bogs at high speed

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g26 pum bogs at high speed

Old 04-01-2017, 01:24 PM
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grant118
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Default g26 pum bogs at high speed

Hi all, I am running my g26 pum in a test stand before putting it in my boat. Using an 18 x 6 airplane prop and water cooling with garden hose. Just trying to get a little run time. Starts good and idles good and runs good up to about 1/4 to half throttle. If I open it up it bogs and will die if I keep opening the throttle. Interesting if I keep the choke just slightly closed the problem goes away. What do you think the issue is? Thanks chris
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Old 04-01-2017, 05:09 PM
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What carb is on it and what are the needle settings? I would try richening the low needle. Doug
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Old 04-01-2017, 05:20 PM
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grant118
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I forget the number but it has a primer bulb and choke. I believe 1.5 turns high speed and about 1 turn low speed
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Old 04-01-2017, 05:37 PM
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I also have a WT257 carb but I have not used that one because it does not have a choke or primer. If I eventually switch to this carb, what are the high an low settings? The engine is a stock G26pum
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Old 04-01-2017, 06:13 PM
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Hi Doug,

I went out to the garage and checked. The carb I am running right now is a WT 644. It has a choke and primer bulb. Let me know what you think. thanks chris
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Old 04-01-2017, 06:35 PM
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Generally the choke is only used for priming the engine as usually it shouldn't get cold enough to use it in your area. This is why you don't see one on your 257. We generally prime with a thumb stuck over the carb while slowly pulling it over a few times until you thumb is damp then pull it over normally.
Try the carb settings at 2 turns out on the low needle and 1 out on the high-speed. A difference as small as 1/8-turn can make a big difference in how these run.

Last edited by Ron Olson; 04-01-2017 at 06:41 PM.
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Old 04-01-2017, 09:13 PM
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firstly don,t forget your running in this engine so really there should not be any full throttle opening yet until atleast 1/2 a galloon of run in fuel is used. you must keep this engine running rich so all moving internal parts have a good chance to seat in correctly , especially the piston ring. as mentioned 2 trurns on the low and i say 1 1/2 turns on the high needle, dont go over 1/2 throttle plus keep plenty of water flowing through the cooling jacket. keeping the choke partially closed for better running indicates the engine / carbie is starving for fuel , so give it more fuel and no choke. make sure your petrol / oil ratio is correct aswell for running in period.
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Old 04-02-2017, 03:12 AM
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thank you for the reply. Chris
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Old 04-02-2017, 07:10 AM
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Thanks everyone I opened the low speed needle about 1/8 of a turn and that seemed to do it. Runs a little rich at idle but throttle pick up is very good with no bogging down.
chris
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Old 04-02-2017, 01:33 PM
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2 turns on the low and 1 on the hi is a good starting point for a 257 carb. I used to run 644's all the time and I ran them with 3/4 turn on the low and 1 3/4 on the hi. A stock 644 is very different than a stock 257. Doug
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Old 04-04-2017, 12:55 PM
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Originally Posted by dwr9 View Post
2 turns on the low and 1 on the hi is a good starting point for a 257 carb. I used to run 644's all the time and I ran them with 3/4 turn on the low and 1 3/4 on the hi. A stock 644 is very different than a stock 257. Doug

Follows Doug's advice above for carb and Zenoah's do not need any real amount of 'break in time' I run 1/2 a bag at varying rpm before I run a new one hard. Bring it in check it and "Pedal to the metal" I certainly would not be running a 1/2 a gallon as break in. Some guys will not run 1/2 gal all day. --- 1/2 gal = 1892 ml - most bags are 500 --- that would be almost 4 bags to 'break it in' ...
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Old 04-04-2017, 03:11 PM
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the main reason you see pistons with scratch and burn marks on new engines is a result in a quick that will do run in period. sure the newer model zenoahs now have a single ring piston were they used to have 2 piston rings , so naturally the run in period could be said to be double that of a single ring. it is wise to make up a batch of run in fuel which should contain abit more oil than what you will use after run in. my fuel mix is normally 50 mls per litre of petrol / gas and my run in fuel is 70 ml per litre. , i run 2 litres [ 2000mls ] of run in mixed fuel with also the main and secondary needles 1/4 turn rich, maximum throttle is just over half but never full . so for a longer lasting engine it is a good idea to run your engine in rich and slow for a few tank fulls then its ready for a long and speedy life. don,t expect to run in your engine in one day at the lake unless you have time to spare as a cooling down period is also needed before re starting plus all bolts etc should be checked for tension plus your shaft will require re oil / greasing often. mistycreek mentioned half a bag of fuel is enough but sorry i don,t think thats really enough for good seating of internal componants like the piston / ring unless the carbie is still set rich.
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Old 04-04-2017, 04:30 PM
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Take advice from those who run real boats - Doug and Ron were right on the money.

Some here will offer you advice - yet they can not post any pictures of any actual boats they run.

Some will offer you advice based on actual experience There is a reason I have over 430 subscribers on youTube - maybe its actual experience. lol

Good luck have fun ..............
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Old 04-04-2017, 05:34 PM
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[QUOTE=mistycreekboats;12323420]Take advice from those who run real boats - Doug and Ron were right on the money.

Some here will offer you advice - yet they can not post any pictures of any actual boats they run.

Some will offer you advice based on actual experience There is a reason I have over 430 subscribers on youTube - maybe its actual experience. lol

Good luck have fun ..............[/QUOTE what do you mean , take advice from those who run real boats ? i have a real boat. not sure where your coming at mistycreek, i am only giving my opinion which is pretty well correct as far as i am concerned, is there something bad about running in an engine by using more fuel ? you are confusing my knowledge as i always thought and have been told to carefully run in any engine and don,t rush it. maybe things have changed these days hey.

Last edited by crapshooter; 04-04-2017 at 06:18 PM.
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Old 04-05-2017, 11:53 PM
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Gentlemen

Your input and contributions are welcome - your feuds are not.

A difference in opinion or experience is to be expected at times.

Please keep to the topic at hand.

If you have issue with one another - please do not use the forum to continue it.

Thank you!
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