New 4a084 Build

[aewrigh]

This is rough and quick but see if it helps any. Any more questions just holler.

[aewrigh]

Just have to remember on these motors, they don't need power to start and run. So the ignition circuit and stop/kill circuits are pretty much separate

[qahqn8]

Hahaha diagram is worth a thousand words. Thank you, more or less what I was thinking! This is my first run with magnetos and I hate running electrical to begin with so I appreciate your help. Would this ignition switch be OK assuming it can handle the final amp load?

https://www.westmarine.com/buy/sierr...oaAtk-EALw_wcB

Thanks again man

[aewrigh]

Looks like it would to me

[Corky]

Here's a pic of a typical magneto ignition switch...One shows the standardized color coded wiring,one shows the schematic of the terminals...There's a few different types to choose from...One on the left has a "push to choke" feature in the switch...Right has no choke but an accessory circuit...Notice how the switch grounds the magneto...

[qahqn8]

Thanks Corky. I've been looking at these. I'm just wired mine last night to a simple two position toggle for when I'm tuning the new carb on the bench. I'm just trying to learn as much as I can for down the road! My one question is the terminal labeled "ignition circuit"... I'm assuming that goes to the choke solenoid on the carb? The terminal labeled "solenoid" should go to starter solenoid right? Thanks!

[qahqn8]

Out of curiosity what kind of tach did you go with? I'd like to stick with something I can just hook up to the magneto lead if possible.

[aewrigh]

I went with a Faria marine/boat tach

[Corky]

I went with a Faria marine/boat tach

Same here faria boat tach...There's a few to choose from make sure you get one that's a 4 stroke NOT a 2 stroke outboard...Here's a pic of the back of mine note the choice of cylinders,input, and the 4 stroke notation...

[Corky]

My one question is the terminal labeled "ignition circuit"... I'm assuming that goes to the choke solenoid on the carb? The terminal labeled "solenoid" should go to starter solenoid right? Thanks!

Iginition circuit would be anything that needs to be on when the engine is running {gauges,etc...} typically that circuit is good to 15-20 amps depending on the switch.. Accessory circuit would be any items that you want on without the engine running {fish finder etc,,,}The rest you are correct...It's really just a different way to describe what aewrigh has drawn up for you...The complicated part comes in when you need to determine just what you want to run through the switch and what will get a dedicated circuit/switch ...


EDIT: I wanted to add this while we're discussing the switch...Keep in mind you may get the switch wet at some point and even a switch that has"non corroding internals and body" might have some trouble if it's full of water...I got one with a rubber cover on it which probably won't help if the key is in the slot while it's raining...Best option would be to have the switch mounted horizontally to get the water to sheet off the key hole...Even I could'nt follow my own advice when I built mine......But I do have a cover that would go over it in the event of a downpour...My small mini has a sealed, plastic ammo box for the console so if it rains I can shut the lid and keep going...

[qahqn8]

OK guys need some advice -

From a financial perspective im leaninn towards the arrowprop redrive, can always upgrade later if necessary. That means I need a starter gear. I like what bgmcl60 did with the Harley gear and flexplate but I know my machining skills are not at the point to get tolerances that close. Other thing is price, the flex plate and 102 bit ring gear at about $150. For $150 i could buy a Briggs flywheel and only have to worry about drilling holes.

https://www.jackssmallengines.com/ja...tratton/693557


Any opinions on this idea and product? Fairly small diameter (11'') and I could take magnets off to reduce weight.


bgmcl60 I'd appreciate your opinion as well since you run that arrowprop redrive. Would an 11'' flywheel clear the bottom pulley?

[bgmcl60]

i tried a 10 in chevy flexplate and wouldn;t clear the bottom pulley with the short belt arrow uses.thats why i used a harley ring gear. 102 tooth is just big enough to reach your starter and small enough to clear the lower pulley. you could buy a longer belt and use a larger ring gear but i used what i knew would work. the chevy mini starter is the right tooth pitch for harley ring gear and less work mounting it and shimming if needed. i bolted the ring gear to center of chevy flexplate and didn't like it and cut down the flex plate to weld on side of harley ring gear. i was a little worried about the temper in the flex plate after welding but it shows no sign of cracking and its been starter more in one night when the mag went out than 6 months of normal use.

[qahqn8]

Hey guys -

Good news got the motor running with the new solex carb and intake from Papee. Idled great, really smooth but it bogged down when I tried opening the throttle up. Im guessing it may need different jets or a timing adjustment? Any thoughts on this would be great. Making progress! Thanks again.

[qahqn8]

Here video of it running with the Brosol carb on it. Like I said in the previous post it idles great (maybe a little fast) but bogs out when I try to throttle up. Anyone who has done this conversion have any suggestions? Thanks.

[qahqn8]

Thinking about this tach... seems like everyone is pretty happy with Faria


https://fariabeede.com/2-pages/aftermarket.php

[Bart]

what is the choke setting? is the choke open or closed when it bogs out?
if the choke is in the closed position, it will bog out the motor with too much fuel.
there are just a few variables to look at before you start making adjustments.
i have found in dealing with multiple carbs on my snowmachines, is to make only one adjustment at a time, then test it. if you make a couple or more adjustments between testing it. you never really know if you are gaining or loosing.
you may have looked at the links below, but i have found some useful information from them in
http://www.vw-resource.com/34pict3.html
http://www.vw-resource.com/automatic_choke.html
i am waiting for a few more parts and pieces for my 084 motor. but i have referred to these web pages, to find the information to do the preliminary adjustments on the carburetor set up that i am going with.
but it looks like you are having fun.

[qahqn8]

Hi Bart!

Yeah the engine is warm and the choke is open when it bogs out. I've seen the links you provided and adjusted the carbs prior to starting it. Im just wondering if the guys who make this conversion can get away with tuning the carb or if modifications to the timing/distributor were needed. You know how it goes, one day in the garage then three doing research!

Glad your build is moving forward. Are you looking for any parts at this point? I'm having a blast with this thing. Its a great excuse to learn a lot!

[Bart]

i found this in the 084 engine thread. this might help you out.
Join DateOct 2008Locationinverness flPosts47

Re: Better carb for 084

well i can tell u all that if u run the brosol solex carb it will in fact run to lean. i did some reseach on the solex an to find out it is set to run super lean. so any one running the solex will have to rejet it.main jet,idel jet,and excellerator pump tube i found that it runs around 450 to 475+ degrees and i think that is to damn HOT. so i got the jets a 170 will flood it out but the stock fuel pump seem to do a good job of keeping up with the demand,so i have been playing with this and i think i got it but i have not had time to hit the water. oh ps i do know where to get the jets after 2 day of hunting
and do not run the 084 to long with a stock brosol solex carb or it WILL melt down

Ron Paxson
Hull: airboat pro 11.6 mini with frog spit
Rig: 1/2 emt
Engine: Teledyne 4a-084-4
Carb: Solex/Brosol H30/31 with main jet 150.needle & seat 2.0 mm.idel jet .55
Reduction: 1.64:1
Prop: 60in warp drive 3 blade 10 degrees pitch
Speed: 38 mph
Max RPMs: 3400
fuel tank: 12 gal
head temp: 350-400

[qahqn8]

Sweet. Good to know about the jets and running hot. Papee had mentioned having to do something with the mag and Im still trying to figure that out. May PM him..

[Bart]

i was thinking about the statement Ron was making, where even though he is running a smaller 30/31 Brosol carb, now most are going to the 34 pict 3 carb .
all of these carbs were jetted to run a 1600 to 1800 CC motor, running this bigger CC motor, there is more air flow going through the carb, so the jetting will be smaller. thus when we adapt the same carb to a smaller CC motor. you have less air flow going through the carb, so all the jetting needs to be just a little bit bigger.
last winter i looked at this quite a bit, and read up on the different carbs that were put on the Suzuki samurai 1300 cc motor. which has to be jetted a little richer to make it work.
i first noticed this when i compared the carb off the 042 to the carb from the 048 motor. in the back of my mind i was thinking that only 2 cylinders, the jetting needed to be smaller, but that wasn't the case j
below is what i found
i posted this with pictures in the "Dual Intake manifold thoughts "
last night I thought I would compare the carb off of the 4A084 to the carb off of the 2A042, just to see what the differences are. thy are a simple carb, but I may not have the correct terms for parts I will be talking about. in the pictures posted below the 4A084 carb will be on the left, and the 2A042 carb will be on the right.

the carb bodies are the same, both are # 13206E1170, on the top of the 4A084,there are the numbers stamped 13620 20hp. and on the top of the 2A042 it is stamped 13619 10 hp

(4a084 ) are the first numbers, (2a042) are the second numbers
metering suction rod (084)outside dia. .093 in. (042) .1225
inside dia.(084) .0550 (042) smaller than3/32 (.0938), larger than 5/64(.0781)
suction hole on bottom side dia.(084) .0420 (042) .0465
feed hole on top by threads (084) .0225 (042) .0420

well nut (084) 3 holes at .0380 (042) 4 holes at .0465

I used drill bits that were available to find the closest size

the same body style of carb had to nearly double all its jetting for half the air flow going through it.
i do remember reading some place on this forum, where someone purchase a new stock carb, and the motor would idle, but would fall flat on its face when any throttle was given, what he found out, he had purchased a carb for the 042 motor, and now seeing the oversized jetting, he went the other way. with a major flooding issue.

i have been following and learning a little from Corky with his build, and have purchased a O2 Wideband analyzer kit to install on my motor. took a gamble and picked up a used one off Ebay for around 130.00
but it it works, i wont be having to second guess what i am doing.
as for any parts at this point, i have enough stuff on hand at the moment. got a new starter coming in the mail. found a good deal on one like what Bgmcl60 has on his build. it only took 2 weeks for them to put it in the mail. so maybe by the end of the week i will see how good of an deal it was.
the fun thing though. last night when we went out playing on the airboat, my wife couldn't believe how fast 3 hours went by. ( that was 3 hours of running it in circles, and the only down time was changing drivers.) me i couldn't believe that i had still over 1/2 of a tank of gas left. so it was a win win.