6hp Chrysler Model 64HD

MickLovin

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Feb 18, 2013
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Hi guys, I got a old Chrysler 1978 model 64H8D, it has spark but doesn't start or even suspect to fire. I put br6hs plugs in and checked for spark, which I have, I took apart the carbie to make sure there was no crap in it. I may need new fule though as I am using my spare tank, but I would of thought I would at least get a fire from it. I have a 12.9HP as well, which fires straight away, but it spews exhaust fumes into the cowl and seems to be running hot. So my intentions are to refit the 6hp with the pull cord attachment that I got new for the 12.9hp and anyother bits I can use for the 6hp my only concern is the lack of firing.
Should I pull off the flywheel and check the contacts, I have spark so seems pointless, I am pretty sure it is a fuel problem, if anyone knows of probs with this motor let me know so I can check it out. :blue:
 
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Nordin

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Jun 12, 2010
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Re: 6hp Chrysler Model 64HD

Does the plugs get wet? How is the compression? If the plugs are dry, check the reeds. If they are wet check the fuelpump diaphragma.

Try this:
Screw out the plugs dry them and put a spon with fuelmix in the cyl. holes. Put the plugs back. Set the throttle to idle and try to start.
If it wants to start you have a fuel delivery problem. Check reeds, clean the carb and check the flotlevel.
 

MickLovin

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Re: 6hp Chrysler Model 64HD

Thx Nords exactly what I was going to try, I have cleaned the carbs and set float level, nut I have a suspicion there may ave been some water in my old can. I will get a fresh can of petrol. I have taken the plugs out and cleaned them but they did seem dry so I will put some fuel in the cylinder and see it it will fire. Thx again.
 

MickLovin

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Re: 6hp Chrysler Model 64HD

Ok I have the motor running, and it runs nicely then misses or sneezes then wants to slow and stop, I have had the fuel diaphram off and it looked ok, but I wasn't getting fuel to the pistons, I cleaned out the carbies again and found a black piece of crap in front of the needle, I also cleaned the jet out and ran fresh fuel. As I said it ran well but missed every 10 - 15 secs then would try to die until I accelerated it up. Could it possibly stll be the diaphragm letting petrol go into the crank, the plugs seemed a bit wet with some black crap on them, I wiped them put them back in and it ran good for a while then started missing, it is pumping water well and isn't getting hot like my 12.9hp.
Any ideas would really help. Just don't want to spend money on a diaphragm and still have the same problem, I do however have another carbie I could use from my 12.9hp and I would just re-jet it?
 

Frank Acampora

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Jan 19, 2007
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12,004
Re: 6hp Chrysler Model 64HD

Black junk behind the needle could be from the diaphragm or the fuel line. SO, you need to check or replace both. Hold the diaphragm up to the light and look to see if any shines through. If so, replace it. If it shows any cracks or flaking, replace it. Replace the fuel line as a matter of course--it is cheap.

When an engine runs well at high speed and trys to or does die at low speed, the low speed circuit is usually the culprit. --That is, unless the RPM are set too low. These engines need to idle at what sounds fast to the ear--700-800 RPM.

At low RPM, there is not enough air flowing through the venturi to allow the dip tube to deliver fuel to be vaporized. At these RPM, the low speed circuit delivers fuel to several metered orifices very near the butterfly (depending upon carb, some are behind, some are slightly in front, and some carbs only have one hole.) At somewhere near 1/4 to 1/2 butterfly opening, the high speed circuit now takes over fuel delivery because there is now enough air flowing through the venturi to create a vacuum.

Sneezing is usually due to a lean condition and you just may have varnish in the low speed circuit. Disassemble the carb and clean it well. Use a very fine copper wire to clean the low speed metered orifices in the body of the carb and if there is a small brass tube running from the bowl to the top of the carb clean it also. (I don't remember the exact configuration of the six HP carb)
 

MickLovin

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Re: 6hp Chrysler Model 64HD

ok sorry to bring this old tchestnut up but I now have no spark, I have fuel coming through after a carbie clean, but now it has decided not to fire on the plugs, I took the flywheel off and the points looked fine, is it possible the condensers are gone and not firing the plugs?
 

Nordin

Commander
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Jun 12, 2010
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Re: 6hp Chrysler Model 64HD

Does both plugs not firing? Yes, a bad capacitor can make the plug not to spark if it is shorted BUT that is not common. I have never seen it.
Check the points and clean them with fine sandpaper and reset them to 020. Take a look at the stopcircuit (if it has one) older 6Hp did not have a stopswitch. It can be shorted/stuck in stop position.
Also check the spring in the boot at the hightension wires. They can be rusty and make bad contact to the plugs.
 

oldboat1

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Apr 3, 2002
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Re: 6hp Chrysler Model 64HD

Hi guys, I got a old Chrysler 1976 model, it has spark but doesn't start or even suspect to fire. I put br6hs plugs in and checked for spark, which I have, I took apart the carbie to make sure there was no crap in it. I may need new fule though as I am using my spare tank, but I would of thought I would at least get a fire from it. I have a 12.9HP as well, which fires straight away, but it spews exhaust fumes into the cowl and seems to be running hot. So my intentions are to refit the 6hp with the pull cord attachment that I got new for the 12.9hp and anyother bits I can use for the 6hp my only concern is the lack of firing.
Should I pull off the flywheel and check the contacts, I have spark so seems pointless, I am pretty sure it is a fuel problem, if anyone knows of probs with this motor let me know so I can check it out. :blue:

Hey Mick -- haven't checked in for a while, and may have missed some discussion on your 12.9. I had a 10 that did the same thing, and did every fix I could thing of -- then found a mouse nest way up in the exhaust housing under the powerhead. Sure sounds like a similar situation (maybe the same mouse, for all I know). Anyway, cleared the obstruction on the 10 and it ran great. (just wanted to mention that)

Little 6 sounds like it's going to be a good one when you get it up and firing again. Condenser replacement could be a good bet. Maybe check coil wire continuity between spring clip and coil.
 

MickLovin

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Re: 6hp Chrysler Model 64HD

Thx oldboat1 Ill check what you have mentioned and get back to you, thanks again.
Doubt if your mouse would swim to Australia, but if he did he's a little mongrel and he can get out of my exhaust. Maybe put him in the mouse Olympics :cool:
 
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oldboat1

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Re: 6hp Chrysler Model 64HD

Yeah, let him live if you find him -- but keep the little bugger there! :)

(best guess, he came over in some cargo hold, stowed away in the leg of an outboard motor. It's what he does.)
 
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MickLovin

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Re: 6hp Chrysler Model 64HD

Just an update after all this time I finally got back to my 6hp and found it's model number isn't 64HD it is 64H8D, in saying all that does anyone know what amount of turns I need for the carbie adjustment?? I don't have a manual that covers this motor. Only 3 & 4 cylinder manual :(
 

oldboat1

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Re: 6hp Chrysler Model 64HD

initial idle setting is one turn out/counterclockwise from seated (1/78 factory manual). Plug gap is .030 (L86 Champions). :)
 

MickLovin

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Re: 6hp Chrysler Model 64HD

Um oldoat1, I couldn't get it started at .030 so I went .020 and got spark straight away. I now have it firing and have it set at 2 turns???
If i set it at less it seems to play up. At the moment it is idling a bit high, so I might play around with the carbie settings for a while till I get that sweet spot. Least it is running now, purring along, can't wait to clean it up and give it a paint. Should look good mounted next to my 100Hp :) Might try to set points again at .030 might have been something else like maybe not grounded properly.
Thanks Oldboat1 least it is running now, it high idles fine and in gear it's fine, just some fine tuning LOL
 

oldboat1

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Re: 6hp Chrysler Model 64HD

running is the key. .030 is the specified gap for the L86 plugs, but if your ignition parts are a tad weak or something (maybe compression a little low) the .020 gap might be the one that works. (that's the point gap, by the way. I don't think I would go any wider gap than that .020) -- maybe shade it less, if anything. The setting I gave for the carb is the initial setting for the idle. From there, you tweak it. You would start the motor (tank preferable for back pressure) in neutral and let it reach operating temp. Shift into gear and throttle it down as low as she will go and keep running. Turn the needle about 1/8 clockwise (leaner) and wait ten of fifteen seconds for engine response -- should hear an increase in rpms. Do it again, throttling down to get back to lowest idle. When she coughs or stops, it's too lean. Turn it out about 1/8 and start it up. Turn counterclock wise (rich) in small increments (like above) until she stumbles -- too much fuel. At that point, find the mid point between too rich and too lean, and you should be good to go. 50:1 mix.

Two turns out seems a little rich, but ain't necessarily so. If that's where she runs, so be it.
 
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MickLovin

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Re: 6hp Chrysler Model 64HD

Thanks oldboaty lad :p your da man, I will check again, just happy she idles and runs now.
 

MickLovin

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Re: 6hp Chrysler Model 64HD

ok I am having trouble with setting it, under the flywheel on the plate is a mark do I line the roller up with that for idle position? It wants to stall if I bring it back to the mark.
 

oldboat1

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Re: 6hp Chrysler Model 64HD

using throttle control, the carb plate should just start to open when the roller touches that point.
 
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