Model Boat Mayhem - Forum

Dry Dock / Shipyard: Builds & Questions => Pleasure boats, Sports, Race, Power and Leisure Boats: => Topic started by: The Doc on October 04, 2009, 12:00:59 AM

Title: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 04, 2009, 12:00:59 AM
Hi all

I have just about finished building my brand new shiny power boat BUT...

Looking for some advice on tuning the carb on my Zenoah clone (QJ 26cc) it has a 1E34FHm.3 carb fitted it has 2 mixture screws and a idle screw the problem i have is I can get a nice tick over but then the engine wont rev as soon as I open the throttle it dies, or i can get it to rev but wont tick over and pops back through the carb at high revs this is a link to the engine you can see the carb quite nicely http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=130213830057&ssPageName=STRK:MEWNX:IT#ht_891wt_939 any help would be appreciated.

Also i want to fit a pulse water pump need advice on where to take the pulse from the inlet manifold or the crank case if the crankcase where is the best place to drill & tap the hole for the fitting.

Will dig the camera out tomorrow and post some pics of the build

Thanks in Advance
Alan (Spain)
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: w3bby on October 04, 2009, 09:41:02 AM
Why do you want a waterpump? Unless you are using a clutch then the pump is just a waste of money, time and effort. If you are really set on having a pump then you can take it off the inlet manifold. Excellent article http://www.modelgasboats.com/Magazine_Content/How-to_Articles/Water_Pump_Install/ (http://www.modelgasboats.com/Magazine_Content/How-to_Articles/Water_Pump_Install/) on how it's done.

Carb is harder.... First take the idle screw and throw it away, use your radio to set the idle. Now you can stop the engine with your radio. Again an excellent article is to be found here http://www.modelgasboats.com/Magazine_Content/Tech_Articles/Carburetor_Tuning/ (http://www.modelgasboats.com/Magazine_Content/Tech_Articles/Carburetor_Tuning/). Of course as the carb is also a clone there is no guarantee that it will work well at all.

I seem to remember reading somewhere that the coils on the clones couldn't handle high rpm as they are rev limited, this could also be part of the problem....
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 04, 2009, 01:02:32 PM
What a great forum this is the information given is exactly what i wanted Many thanks W3BBY yes i am running a clutch i have a pulse pump already seems a shame not to use it.

Many Thanks
EA7/G6SDM (Albox Spain)
Alan
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 04, 2009, 01:43:00 PM
Hi Alan as webby says the coils on those motors are not good but you can swap it for a zenoah one i believe and that will help the performance.
Mart
Heres a link to the coils
http://www.oneillbrothers.com/rcboat/rebuild_ignition.htm

heres another good source for certain parts also genuine walbro carbs etc.he has been known to stock the zen coils too maybe ask him ?.

http://stores.shop.ebay.co.uk/Head-of-the-River-RC-specialist_Marine-Engines-accessories_W0QQ_fsubZ7471304QQ_sidZ367965989QQ_trksidZp4634Q2ec0Q2em322
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 05, 2009, 11:24:24 AM
Hi Mart

Thanks for the info, the second link for ebay you posted is where i bought most of my stuff including my Hull good shop fast delivery as well.

I took the boat to the lake yesterday disaster had loads of agg with the motor just cant get it to run smoothly just keeps stalling and is a bitch to start (i am a motor mechanic myself) not used to working on things this small tho i have resigned myself to strip the cylinder i am sure there is a air leak somewhere i have installed a pulse water pump that don't work ether followed the install instructions to the letter as i see it the pulse pump wont work if there is a crank case leak still will strip it in the next couple of days.

Thanks for all suggestions

Alan
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 05, 2009, 01:08:45 PM
A Few Pic`s

Alan
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: Bill D203 on October 05, 2009, 04:41:55 PM
Hi Alan.
 I have been ruining petrol engine OMRA boats for just over 2 years now. I am NO expert but i was always told but people who know the folowing.
Screw both the high & low needles fully in. Then take them both out 1 1/2 turns.  The needle nearest the air intake is high end and the other low end. They are marked with a H & L. This is where to start from. The engine should run. The Idle screw, take it out and don't use it. Set up your servo to fully close /stop your engine.
Now then when you get the engine to start you may well find if you close / open the High needle 1/4 turn it will rev very well. However this is where every engine set up is a different. Thats the bit you need to adjust till you get it right.  The low end needle may also need closing a tad.
I did have on one of my boats a pump set up. the pick up was in the black carb isolation block into the main air way. It has been said if you are not using a clucth then there is no need to fit a pump as the water pick ups will supply all the cooling water you need.
Did you get the engine from new? If so the crank casein gasget should be fine and it is just down to carb settings.
Taking a look at your photos. You need some place for air to get into the boat. Engine need Air to make them work. You seem to have 2 water pick ups on your rudders pipe one to the c/head and the other to the ex pipe cooler bits.  One more thing. Disconnect the stop swicth/red button. It will fail when it fills with water and the engine will not start. Its all done by the servo.
Anyway Best of luck :-))
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: brodjack on October 05, 2009, 06:26:35 PM
Bill is right you need air intakes,my son has the very same hull,nice looking boats,easy to setup and run.
We cut out the two intakes on the front deck for air.
Afew pics and some video from last yr.

http://www.youtube.com/user/jackbrod#play/all

Brod..
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 05, 2009, 08:08:56 PM
Thanks for your comments Bill & Brodi

Brodi any chance of a few pics of your boat just want to compare the way you have fitted it out

I have tried every which way with the adjusting screws just cant get any sense out of it at all the biggest issue i have is starting the thing its a bitch i have tried all positions with both the running screws i can get a sensible tick over but as soon as i touch the throttle it dies no mater where i adjust the screws the only way i can get it to rev is to "xxxxx" up the tick over but it don't rev nice its misfiring all the time the other issue i have while i am trying to sort it out the engine is getting a tad hot as i said in my last post i have fitted a pulse pump so i could set it up in my pool but the bloody thing dont work ether which makes me believe there is a crank case air leak quite a bad one that would explain why its a "xxxxx" to start...unless any one knows better.
   
I will cut out the couple of air intakes is there any grills to fit does anyone know.

I do appreciate all your help and comments

Alan (Sunny Spain)
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: brodjack on October 06, 2009, 11:18:00 AM
I wouldnt bother with grills on the holes,more restriction.more air is better,especially where you live,(lucky guy).
jack said 'wow' when he saw your pool.
I'll see if i can dig some inard pics out.
Brod..
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: Dreadstar on October 06, 2009, 11:23:31 AM
Re-set both the high speed and low speed needles back to their factory settings,and make sure that the throttle stop screw is set so that the carb is only open by 1mm when the throttle is in the closed position.Make sure that the glow plug is glowing properly,and that you're not using too hot a plug.Once you can get it running,lean off the high speed needle 1st in 1/8 turn increments,until no further improvement is noticed. Then start leaning off the low end needle,an 1/8th of a turn at a time. Nitro engines can be extremely frustrating to set up correctly,something I've had a lot of experience with,coming from 1/8th nitro off-road racing. I know that the engines are different,but the principle should be the same.

 Good luck Doc.

David.

OOPS,I didn't realise that this was a petrol engine......... :embarrassed:
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: Bill D203 on October 06, 2009, 05:56:44 PM
Well Spoted Dreadstar.
26cc Zenoha have a spark plug Opps
I still don't know why he is having so many probs with it. Still if he dose take it apart it may reveal a leaky crank case but I still think it is down to the carb setting or leaking gasgets on the carb somewhere. I hope he finds it very soon and starts to enjoy his boat. Best of luck.
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 06, 2009, 11:27:23 PM
Might be the coil is duff,also check your mounts arent anodised or you wont get a good spark if at all.If the mounts are anodised a grounding strap can be used or simply file off the anodising where the contact area for the coil is on the mounts
Mart
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: Bill D203 on October 06, 2009, 11:55:15 PM
Might be the coil is duff,also check your mounts arent anodised or you wont get a good spark if at all.If the mounts are anodised a grounding strap can be used or simply file off the anodising where the contact area for the coil is on the mounts
Mart
Hi Mart
Good to here from you. Thats a good point.  As I said I am no expert so some of the basic things could get over looked.
Cheers
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 07, 2009, 07:01:49 AM
Thanks for all you comments I will be dusting of my tool box tonight I particularly like the anodising theory i have fitted a new shiny anodised coil re locater Hmmm

Thanks again

Alan
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 07, 2009, 09:36:40 AM
Sounds like that could be it then so two ways you can sort it 1. remove the anodizing and 2. run a grounding strap or wire back to the engine casing.Also check your spark plug boot conector,what plug are you using? sometimes just changing the plug can make a difference,dont use champion plugs they break and can go inside and ruin a good motor even on the first run.Good luck  ;)
Mart


Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 07, 2009, 06:20:18 PM
Heres a pic of what the grounding strap looks like you can buy em at the auto store but you will know that im sure ok2.Bill hows you m8,just putting another issue or idea out there that ive come across myself.
Mart
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 07, 2009, 11:20:40 PM
Thanks again everyone

Well good news found the main problem the pulse hole in the cylinder block that couples to the plastic carb mounting block was obstructed with a piece of gasket couldn't see it was a 'xxx' to clear had to take the cylinder of and blow it out with compressed air engine now starts nicely and ticks over and revs not to bad (still a problem will get to that in a minn) AND the pulse water pump now works. I had it zipping round my pool tonight at a vast rate of knots the turning circle is fantastic my pool is 5 meters wide and 12 meters long and it got round no problem. Ok now for the remaining problem as i say engine ticks over and revs nicely well sort of it starts to hold back at about half throttle and pops back through the carb not sure if its at max revs tho just like it has a gigantic flat spot if you move the throttle from tick over to half stick alls well but as soon as you give it full stick it (for want of a better word) bores and pops back through the carb but it seems to have plenty of revs and power suppose i wont find out till next Sunday will keep every one informed.

Yet another question any advise on what prop i should use i have fitted Aluminium propeller dia 70mm pitch 98m is that about right or what do you all think?

I will install a grounding wire i have some flat braiding i can use just in case.

Well till the next instalment Ta Raaa

And Thanks again
Alan
P.S. Martin the rigger looks like its doing a 100 miles an hour sitting on the bank looks very nice.
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 07, 2009, 11:53:51 PM
Glad you found the problem,best way to tune the carb is on the water so get it out there and fine tune it.The prop sounds ok for a first prop,theres plenty of good props out there though.See how it does and you can go from there.I wish that rigger was mine i borrowed the pic to show the ground strap lol.Checkout my website for pics of the boats i build,and checkout my youtube page for videos of some of my boats mainly my hydro  ;).
Mart
http://www.youtube.com/watch?v=919dKyiA1lA
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 08, 2009, 09:09:36 AM
What i will say about props is buy a few as you can never have too many options,they are an investment.Try the x472 theyre good mono props also i like the propshop 6717/3 from dasboata tell him its for a mono with stock motor he will do the rest.Or just tell him your setup and he will tell you which prop would suit,his props are the best he does great work on the sharpening and ballancing and modding them etc.No two boats or setups are the same so its a case of experimenting till you find the right prop.
Mart
heres his site be sure to email him to get a race ready prop
http://www.dasboata.com/
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: Bill D203 on October 08, 2009, 06:34:23 PM
Nice Rigger Mart. I think I want one!!! Lets see if that old git Father Christmas will bring me one?  NO! oh well worth a try.
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 08, 2009, 09:50:45 PM
Bill its not mine i just borrowed the pic to show the strap lol,my firefighter rigger is still on paper i havent had time to build it yet  ok2.
Mart
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: Bill D203 on October 08, 2009, 10:18:00 PM
Bill its not mine i just borrowed the pic to show the strap lol,my firefighter rigger is still on paper i havent had time to build it yet  ok2.
Mart
Hi Mart
It's nice dreaming! one day.
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: zenman63 on October 10, 2009, 11:19:16 AM
Heres a pic of what the grounding strap looks like you can buy em at the auto store but you will know that im sure ok2.Bill hows you m8,just putting another issue or idea out there that ive come across myself.
Mart

Rigger looks nice.
The QD water cover is the wrong way round and will trap air in the very top and over heat  ;)
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 12, 2009, 07:25:08 AM
Well took the boat to my local lake for its maiden voyage and it went like a dream don't like saying this but it went without any problems at all.
Would like to thank all the comments and help from the forum members here is a small video clip is there any comments on how its riding seems to go very well turns on a tanner

http://www.youtube.com/watch?v=TD9VrN-Gn_k


Looking forward to more comments

The Doc
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: brodjack on October 12, 2009, 09:01:58 AM
Nice to be back on topic again.
Looking good,these hulls run easy and well,yours maybe a bit wet,you can raise the trim tabs a bit to get to it to run drier,worth a try now its running.
Its a very fine line between wet and dry with these low transom hulls,in rougher water it might need the tabs lowering,if you know what i mean.otherwise good run.
The motor will produce a bit more power when you've done a few tanks.
What prop are you running?
A 7015/3 made a big speed differance with my son,Jacks,boat,same as yours.perhaps 5-6mph.
Looks a good place to run.
sorry couldnt find any old pics of the inside of his.
Brod..
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 12, 2009, 10:09:35 AM
Congrats on the maiden Doc she just needs tweaking ,id start with the carb then pipe length push it in1/8"at a time till the revs pick up and run it to test and keep going 1/8 at a time the revs should really pick up and just keep going like this till the revs drop again then back it out 1/8" that should be your perfect tuned length.
Mart
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: Patternmaker on October 15, 2009, 09:43:02 PM
Hi Doc, you my be interested in a boat I built its listed in Sports boats under
28CC WEEDWACKER MODIFIED TO WATERCOOLED MARINE ENGINE
It's the same hull as yours, the chap who bought it from me says he is getting 50mph plus it running a 70mm 110mm 3 bladed prop.

 Mick.
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 16, 2009, 07:34:30 AM
There`s more

http://www.youtube.com/watch?v=0rTaV1GQu0k

Alan
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 16, 2009, 10:47:54 AM
How the hell do you modify a post i have done it b4 but the option is not there now. >>:-(

Hi Mart

Thanks for your comments i will be at the lake on Sunday a day of tweaking.

And thanks for your comments Mick i am running a X470mm prop at the moment i also have a new 478 i am going to try on Sunday 

Thanks all
Alan
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 17, 2009, 08:56:53 AM
Hi Allan still needs tweaking but you know that  ;),keep playing .Id think the 78 mm prop will be too big for it.Best bet is make sure your using a sharpened and ballanced prop then you know you have a good prop etc.The 470 is a decent prop so as long as its sharp and ballanced its a good start,then tweak carb and play with pipe length and also strut depth etc,try to keep the prop parallel to the hull  or as near as you can.If all else fails try changing the coil for a zenoah one as some of the clone ones do restrict revs.Heres a few scans taken from a good book by John Finch they might help on trimming the hull in etc.
Mart
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 17, 2009, 02:25:19 PM
Wow thanks Mart

Have printed out the information will spend most of tomorrow tweaking and having lots of fun doing it. (must remember the heat proof gloves for the exhaust)

Got to be honest the handling is what i consider spot on it don't wander it corners like nothing i have seen before must be something to do with the twin rudder it corners spot on at full power comes out of the turn straight as a die.

I take on board what you say about the prop i have fitted the 478 prop it will give it a go for comparison will take the 470 with me to swap back.

Mart where abouts are you in Blackpool my best m8 lives there he used to have the Cresta Hotel in Withnell road near south pier he has now moved to cleaveleys John Snelson is his name i know Blackpool is a big place I Love it if i ever move back to the UK that's where i will move to.

Thanks again for your comments will update this thread tomorrow night

Alan



Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 17, 2009, 03:24:15 PM
Have fun mate thats what its all about  ok2,ive been in Blackpool for 14 yrs now i live away from the main town not far from Bisbham and a five minute drive from Cleveleys.If you ever decide to move back let me know id gladly swap with you  O0.
Mart
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: omra85 on October 18, 2009, 03:39:51 PM
Thanks for this information Mart.
I knew what happened when you did various adjustments - now I know why.
Danny
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 18, 2009, 09:27:44 PM
Thanks for this information Mart.
I knew what happened when you did various adjustments - now I know why.
Danny

No problem Danny it made things a little easier for me to understand why certain adjustments did what too.Mind you some say cats are different so then things can get confusing lol.The book is called advanced rc boat modeling,its a good read and some good tips in there for anyone.
Mart
http://www.amazon.co.uk/Advanced-R-C-Boat-Modeling/dp/0911295216
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 20, 2009, 12:16:48 PM
Hi all

Well it went very well again i did tune the exhaust and the 478 prop did make quite a difference so will be leaving that on.

I should have another video shortly i will post it as soon as i get it.

My friend that went with me he fell in the water the engine stalled on the boat about 4 ft from the bank he said he would get it but the banks was very slippery he was leaning out with a twig and in he went right in mobile phone and all good job the sun was shining and warm he striped of and dried his clothes   {-) shouldn't larf but it was very funny phone did start to work again when dried out O0

Thanks again for all your tips and advice between as all got it going nicely :-))

Alan
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: martno1fan on October 20, 2009, 12:59:34 PM
Wish you had got that on video  :D,glad its working out for yaa though.
Mart
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: ids987 on October 20, 2009, 04:58:55 PM
Some more from John Finch in the attachment. This is a compilation of three articles entitled Mono Mania - which some may have heard of. I think they have been posted on here before.
Title: Re: Help wanted tuning carb on Zenoah clone
Post by: The Doc on October 20, 2009, 05:40:14 PM
Thanks for that Ian nice bit of reading matter for tonight cheers

Regards
Alan