Clone in a Marathon

AirJunky

Finally getting started installing a 16 hp clone in my Marathon. I went with a Durastar from Maxtool.com, which is apparently just like the blue Duromax. Cost was $290 shipped and it just showed up today. It's got electric start & no charge system. I plan to keep the EZGo starter/generator like some of you have already done.

I pulled the rear swingarm out of the cart last weekend. I'd like to get rid of the 3" block lift & have ordered a pair of Monroe Sensa-Trac shocks for the rear suspension. I understand that combined with the stock Marathon coils, I'll end up with about 5" of lift (2" more than I had), more travel & able to haul more weight. Still on the fence about extending the swingarm hinge point like some of you have. I guess I'll have to decide when I have the engine mounted on the swingarm & mocked up under the cart.

I'm using a stock clutch & adapter I picked up from CPP so I have the pulley for the starter/generator belt. My old clutch was slipping a ton, guess it finally gave out after 19 yrs.

This evening I pulled the Durostar tank, air cleaner, exhaust & governor. Lots of Youtube videos on how to remove the governor so it was pretty easy. As you can see, I am going to have to cut the crankshaft as the pulley is about an inch away from the crankcase. Will a portaband be OK for cutting the crank? I'll need to pick up a good blade for it, plus I need a good drill bit & tap for the clutch bolt. I believe it's an M8 x 1.25 bolt.

Unfortunately I will only get a chance to work on it on Sat afternoon & Sun morning. I'll need to pick up the blade, drill bit & tap tomorrow. But then have to go to work for a few hours.
I'm hoping to get it all mounted on the swingarm before the SuperBowl starts.

Question for you guys who have already done this. If you removed the governor, did you remove the gear & weights too? I'm thinkin all I need to remove is the arm itself. I plan to get the vacuum pulse for the fuel pump from that hole.

Attached Images

	engine5.jpg (63.8 KB, 93 views)
	engine4.jpg (62.9 KB, 90 views)
	engine2.jpg (76.3 KB, 127 views)
	engine1.jpg (75.9 KB, 97 views)
	long crank.jpg (56.5 KB, 115 views)

BGW

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

mbolan

Definitely remove the plastic gear and weights. It just pulls out and you won't have to worry about those pieces coming apart in your engine. The porta band will work fine just keep it square to the shaft so you get a straight cut. A cut off wheel on a angle grinder works great also. I drilled my pilot hole in the crank before I cut mine but I didn't cut nearly as much off as what you are planning.

mbolan

Air junky I think I misread about how far you were cutting the crank. I thought you were cutting the crank so that only 1 in was left sticking out. Point being that you should drill the hole before you cut if possible so you can use the existing hole as a pilot. My Duromax was a standard thread. I actually could not find one without speacial ordering because it was a fine thread. I was to impatient for that so I ended up making a stud from a piece of 3/8 rod and putting a nut on the end.

AirJunky

Thanks mbolan. I expect I'll need to cut about 1/2" to 5/8" off the crank, giving me less than 1/2" clearance between the pulley & the crankcase, which is about what the stock EZGo engine & pulley had. Thanks on the pilot hole tip too.
I didn't think the gear came off as easily as you mentioned. Youtube videos mentioned it having a c clip on the stud, but I couldn't really see that. I'll open it up & check that again.

pachanga90

You could use a cut-off wheel on a 4" grinder to cut the crank.Take some masking tape,and go around the crank,using the edge of the tape as a guide-line for your cut.When you cut,just stay tight to the tape to keep it square.The pilot-idea is good to.Mark the depth you need on your drill-bit and drill from the stock hole.We used to do this when we raced go-karts.Don't go by the dimension on your stock motor.Get the new motor in and check pulley-alignment.I don't think you want to install it and find out you needed the 1/2" you cut off.Always remove all parts for the govenor,They can fly apart at high rpm and they will wipe out the motor.When we raced Go-Karts we removed the recoil-starter,because it could engage at high rpm and explode.Any hole in the crankcase will give pressure,not vacuum.You will have to find a location in the carb or intake manifold(after the throttle-shaft,but before the port)and drill/tap as needed.Hope this helps.

rokcrlr

Your not wanting a vacum for the pump, your wanting a pulse. The govener hole will work, but it also will get oil in your pulse line. Some guys pulse off the valve cover below the inside baffle but also are saying the baffle is too low.A carb spacer could work but then it moves your carb further and you already may have clearance problems. The crankshaft gov gear slings the oil at the gov holeand throws the oil around that is where you will get the oil thru the gov hole. You can find a thick part of the block on the timing gear side and drill and tap there and shouldn't have as much of an issue with oil getting in the pulse line.

pachanga90

When we raced Karts with 4-stroke Briggs 5hp.we always hook to the intake manifold with a pulse-pump,remember its' a single-cylinder so it "pulses" rather than a constant vacuum like a multi-cylinder.Going into the crankcase can work but i wouldn't do it,mainly due to slugging up the pump and line.You will only need an 1/8"-3/16" hole to put a fitting in,so room shouldn't be hard to find.2-strokes hook to the crankcase because its' under vacuum,4-strokes are pressurized,with small vacuum pulses when the piston is at TDC.Hope this helps.

mbolan

I used the gov hole for a pulse. I read on one of the kart racing pages that on the small block clones they would get oil in the line because its located lowwer on the engine, but that it wasn't a problem on the big blocks since the hole is on the top of the motor. I suggest using it since its free (no cost). The way I see it air is only moving back and forth a little bit so its not like its drawing it into the pump. When some oil or oil vapor gets into the line it will tend to gravity drain back out. I only have about 5 miles on my cart but I just went out and pulled the line to check. So far no sign of any oil.

AirJunky

Thanks guys. I'm going to try the governor hole first. I can always move it if I have to pick up a spacer or anything.

So I have the EZGo stock clutch (tapered) and the CPP adapter. It looks to me like I need to cut like 1.5" off the crank to get the pulley about 1/4" - 1/2" from the crankcase. I can put the adapter into the clutch & it'll only go in the tapered hole maybe 3/4". Doe this sound right?

Guess I'll call Tom in the morning.

sho305

I tried the governor hole and it filled the pump with oil and quit working. The crank slings oil right there. Better to drill a hole in the side cover is what I saw in other engines, between the webbing there. I ended up buying (they are cheap) another intake spacer with a tube in it to replace the stock one. TheNewGuy drilled his own hole in the spacer and epoxied a tube in it. Or try to drill a hole just under the rocker cover. The crankcase pulse will work better, the intake pulse reduces with more rpm, but either works. Ours it overflowed the carb and we had to put a return line in, at idle it did that.

On one I did the governor I pressed the shaft out of the side cover, removed gear, pressed shaft back in empty. Its in my post in yamaha gas:
http://www.buggiesgonewild.com/gas-y...cs-thread.html
Think I used a big grinder with a cutoff blade to cut it, but I've done them with a hack saw just takes a good blade and some elbow grease its not that bad. A portable bandsaw would be ideal. I would put it together and mock it all up, make sure you have it right. Maybe the adapter sticks out of that one, it went into the yamaha all the way.

I held a rag in the engine and drilled and tapped the governor hole and put a pipe plug in it.

Look at the fittings in the side cover here: http://www.affordablegokarts.com/fuel-pump-setup.php
Doing the next one that way hope it works, or up top.