By Willie (Willie) on Unrecorded Date: Edit

Hi Gang,

I’m a new owner of an old Argo with a Tecumseh OH160. I’ve got a new carb and impulse pump and it runs great at low rpm (or high rpm sitting in the garage!). At higher RPM under load it craps out on me. Suspecting fuel delivery, I installed an electric fuel pump in line and it runs OK under load. The eliminates potential problems (or so I think!) with float level, new carb, electrical, and tank venting. Pretty much pinpoints impulse pump. I don’t want to rely on an electric pump though, since I intend to go to some pretty remote places.

As it works fine when not under load, I think I’m getting close by narrowing down that the vacuum for the pump craps out under load at higher rpm. Suspect of rings or head gasket? Compression is in the 90’s, a bit low but not too bad. That’s just turning it over though; maybe these other things are just minorly buggered and not showing up until under load? It there anything else I should look for? Oil level is bang on, as I know that’s important for the pump to work correctly.

Thanks for any help that can be provided. And please, no “shoulda bought a Max” crap, thanks, I’m just here to get some help with what I have.

Willie

By Attex Bob on Unrecorded Date: Edit

Willie: I have the same problem with my Argo with the same motor. I've rebuilt the pump and took the carb apart several times. I've checked the lines and tank venting like you have. I know mine runs out of fuel, but I just can't figure out why. It's not a fresh motor problem because mine has about an hour on it from rebuild. When you figure it out let us know!!!!

By scrambler71 on Unrecorded Date: Edit

to both willie and bob
from scrambler71
i have a old 160 tecumseh in my 71 scrambler
and i had a fuel delivery problem with mine and i to take
take off the fuil pump off of it
and i am putting a elecric fuelpump on
the return line
i should have done this a time a go
if i was you i would get elecric fule pump that
solve your problem
when it happen to me it was newyork at the
humprey ride last year and it keep me from ridding
not this year i am going ridding
and nothing going to stop me from going

By Sam Keys on Unrecorded Date: Edit

Get a electric fuel pump ?
also have a fire man around,
see Route6x6 Tips and Hints section

Sam Keys

By Sam Keys on Unrecorded Date: Edit

Get a electric fuel pump ?
also have a fire man around,
see Route6x6 Tips and Hints section

Sam Keys

By Willie (Willie) on Unrecorded Date: Edit

Thanks Scrambler.

I've read in another bulletin in here that the electric fuel pumps produce too many psi (about5) and can push the needle and seat open and cause flooding. One of the bulletins warns of electrics as they keep pumping even when the engine stalls and can end up puking gas all over. There's a pic of one Argo melted right down to the ground, because the electric pump kept on suppling fuel to a backfire spark!

Anyway, for now I am running the impulse on low rpm and switch on the electric when needed, but am looking for a more permanent fix. As I said, I don't want to rely on anything electric where I plan on going, and unless you can find a low psi pump they might be a bit too much.

Thanks. Willie

By Willie (Willie) on Unrecorded Date: Edit

Thanks Scrambler.

I've read in another bulletin in here that the electric fuel pumps produce too many psi (about5) and can push the needle and seat open and cause flooding. One of the bulletins warns of electrics as they keep pumping even when the engine stalls and can end up puking gas all over. There's a pic of one Argo melted right down to the ground, because the electric pump kept on suppling fuel to a backfire spark!

Anyway, for now I am running the impulse on low rpm and switch on the electric when needed, but am looking for a more permanent fix. As I said, I don't want to rely on anything electric where I plan on going, and unless you can find a low psi pump they might be a bit too much.

Thanks. Willie

By david berger (Davidrrrd) on Unrecorded Date: Edit

willie,
i think he sugested adding the elecrtic fule pump
TO THE RETERN LINE, maybe it reduses chance of overloading carb?

By mike martindale (Wetsu) on Unrecorded Date: Edit

i am toying with the idea of an auxillary fuel tank.mainly to be used for climbing hills,since my bigfoot tends to stall when i climb any steep,or long grade. has any one else considered or even tried it??i want to mount it under the hood towards the front of the machine,so to let gravity work for me instead of against me.

By Willie (Willie) on Unrecorded Date: Edit

Attex Bob,

Got it figured and running great. With the old carb, the impulse pump was mounted directly to the right hand side of the carb. The new carb has the inlet on the left side, and the impulse pump is a remote mount (meaning it doesn't screw directly into the carb).

As I thought it best to keep the vacuum run to the pump from the motor as short as possible, and as the inlet of the carb was now on the left side, I positioned the pump about 4" below the inlet and on the left side.

I read on another article in here the the impulse can't pump much more than 1 foot of vertical. I figured that maybe this extra 4" of lift from the pump to the carb was too much, considering the distance from the tank the pump already had to pump.

Also, when climbing, the tank drops below the level of the carb. The fuel was then being pumped up to the level of the fender well (creating a high point), dropping down to the fuel pump, and then up to the carb. On a decent uphill acceleration, the pump couldn't handle all this. I think it lost prime and created an air lock at the high point.

I've now got the pump installed a bit higher than both the fuel tank and the carb. It maintains a positive grade the whole way from the tank to the pump, so eliminates the chance of a high point and therefore an air lock. The pump only has to pump from the tank, and can now flow by gravity into the carb (now about 3-4" above the carb inlet). It now has no problems keeping up.

One other thing you should check if you happened to have installed a new carb. The original carb had a small air breather port at the bottom where the air cleaner bolts on; the gaskets have a square cut-out for it. The new carb has this port about 3/4 of the way up the right side, so your air cleaner plate needs have the sheet metal removed to create this port. The gasket can be used as a template, and I used a small round file and it worked slick. Don't do it with shears or snips as that may bend things and bugger up the seal with your gasket.

Anyway, hope this might shed some light on your problem!.

PS...guys, what return line have you been referring to in here?

Willie

By david berger (Davidrrrd) on Unrecorded Date: Edit

WILLI, I BELEAVE THERE TALKING ABOUT A DIFERENT CARB,WHEN THEY TALK ABOUT A RETERN LINE, LIKE A TILOTSEN MIGHT HAVE OR SOME OTHERS,
THATS GREAT INFO PLEASE GIVE PRT # FOR CARBS TO HELP COMPLEAT YOUR DISCRIPTIONES IF YOU CAN, ALL THIS HAS ME WONDERING JUST HOW MANY PULS PUMPS CAN SOMONE USE AT THE SAME TIME,
I WONDER IF 2 OR 3 CAN BE SPREAD OUT THREWOUT THE LINE TO THE CARB TO INSURE CONSTANT FULE DILIVERY?

By Willie (Willie) on Unrecorded Date: Edit

David,

Remember though, each impulse pump would require a vacuum line back to the crankcase, and if you tried to split the vacuum signal 2 or 3 times it would probably weaken the signal and provide a whole new set of complications. You might end up with 3 pumps and none working properly! The impulse pumps aren't cheap either.

Willie

By david berger (Davidrrrd) on Unrecorded Date: Edit

YES I KNOW,
BUT IM ONE OF THE GUYS WITH A TILOTSEN CARB PROBLEM, ITS GOT IT'S PUMP INTERNAL SO IF IT DOSENT QUITE HAVE THE GUTS'''
WELL IM TRYING TO FIG OUT WHAT WILL HELP IT, SHORT OF AN ENGINE REBUILD, WICH WE KNOW MAY NOT SOLVE THE TROUBLE,
IF I CAN FIND SOME PLACE TO GET A VACUME PULSE FROM THAT ENGINE I'L TRY ANOTHER PULSE PUMP INLINE AS A BOSTER,IF IT OVER LOADS THE CARB THEN I'L TRY DAVE YODERS SUGETION OF ADDING ONE TO RETERN LINE, WHAT THE HECK , GOT TOO TRY SOMETHING, I HAVE REBUILT THE CARB ABOUT 12 TIMES,

By liflod (Liflod) on Unrecorded Date: Edit

What problems are you having with the Tillostson carb? I finally removed mine and put a Mikuni on it. I have everything ready to start it up but its too damn cold and dark after work to go outside and try it. I will let you know the performance improvement if any with the Mikuni. My wife's machine with a single Mikuni flies! The tillotson gives me hell trying to get it started. Once its started it runs fine, but doesn't have the power of the Mikuni machine.

By Jon on Unrecorded Date: Edit

Hi There

I had problems similar to what people are describing above with my Magnum. Replaced filters,pump, Carb kit etc. Make a long story short it turned out to be the fuel line itself, must deteriorate & collapse inside with age.

Jon

By david berger (Davidrrrd) on Unrecorded Date: Edit

RUNS GREAT TIL IT RUNS OUT OF GAS, THE PUMP HAS BIN REBUILT OVER AND OVER, PROBLEM IS PULSE COMES FROM THE BLOCK BEHIND CARB, OK FOR TILOTSEN BUT TO CHAINGE TO MCUNI I NEED ANOTHER SOARSE OF PULSE,
WICH IF I HAD ONE I COULD ADD ANOTHER PULSE PUMP INLINE TOO HELP THE TILOTSEN IN THE FIRST PLACE,
LOCALE SHOP DIDENT HAVE ANY SPACER BLOCK'S
ID DRILL A HOLE IN ONE AND TAP IT WITH A BRASS NIPLE FOR THE PULSE TO RUN AN INLINE PUMP BUT GOT TO FIND ONE TO EXPIREMENT WITH FIRST

By liflod (Liflod) on Unrecorded Date: Edit

Dave,
What engine are you running? Is the problem after you run out of gas or is it leaning out? Make sure you are using a reinforced hose for the vacuum signal to the carb. If the hose is not rigid, the hose will just absorb the vacuum pulses. I have some extra Tillotson plastic spacers, but I don't think the extra pump will help.
When I bought my first machine, it had 2 Mikunis on it. After talking with some people, they said it would run better with one carb. I put the Tillotson on it and the throttle response was much better and all around drivability was better. Trying to get it started turned into a real treat. I was pretty happy with the setup until I put my wife's machine together with a 440 cuyuna and a mikuni.It will start right up (with a pull stater no less) and run like a raped ape! I finally modified the intake on my machine to accept the Mikuni and modified the throttle cable and choke cable to work. I should have my machine running and tested this weekend.

By david berger (Davidrrrd) on Unrecorded Date: Edit

ITS A STOCK SET UP ON A 440 ROTAX, IT JUST RUNS GREAT! THE CARB JUST WILL NOT PUMP IT'SELF FULL, I CAN DO IT WITH AN INLINE BOAT TYPE PRIMER BULB BUT THE PUMP INSIDE CARB WON'T STAY ON THE JOB, MY PULSE COMES FROM THE BLOCK THREW THE SPACER AND INTO THE CARB, MOST LIKELY ENGINE NEEDS WORK BUT IM NOT PLANNING TO GO THAT ROUTE, I DID IT TO ANOTHER 440 AND IT WAS DESTROID BY THE REPAIR PEOPLE, COST AN ARM N LEG AND THEN I STILL HAD TO BUY A NEW ENGINE, NOPE IM GOING TO FIND ANOTHER WAY TO GET GAS INTO THE BUGGER, EVEN IF THAT MEANS USEING AN ELECTRIC PUMP, I HAVE ALREADY BOUGHT A LOW PSI REGULATER FOR IT JUST IN CASE I HAVE TO GO THAT ROUTE, I TOO HAVE ENGINES WITH MACUNIS AND LOVE HOW THEY WORK, THAT IS WHEN THEY WORK, THEY CAN RUN FINE FOR 10 YEARS BUT WHEN THEY DON'T YOU NEVER FIGURE OUT WHY,
I HAD SOMEONE TRY TO TALK ME INTO CHAINGING MY MACUNI CAUSE IT WOULD START BETTER WITH A TILOTSEN? I DIDENT CAUS MY MACUNI'S STARTED GOOD JUST WITH THE ENRICHMENT VALVE, HOWEVER SOME OF MY VEHICLES DO HAVE LITTLE PRIMER PUMPS TO HELP THEM START, SOME TILOTSENS HAVE A LITTLE BRASS TUBE IN BASE FOR A PRIMER INLET, THEY DO START VERRY WELL WITH THE PRIMER PUMPS,

By liflod (Liflod) on Unrecorded Date: Edit

Check the return line fitting on the carb. It should have a really small hole in it to restrict the amount of fuel returning to the tank. If the fitting does not have a restriction all the work of the diaphragm pump is just pumping fuel from the tank through the carb and back to the tank. It needs the restriction. I would highly recommend the primer if you plan to keep the Tillotson. You can probably just drill a hole in the manifold and JB weld a small diameter brake line tube into it for a primer fitting.

By david berger (Davidrrrd) on Unrecorded Date: Edit

NOPE IM PRITY SHURE THAT AINT IT,
IT RUNS LONGEST WHEN I PUMP THE LINE THREW THE CARB AND BACK TO TANK FULL WITH GAS BEFORE I START IT, THEN WHILE ITS RUNNING I CAN SEE GAS SLOWLY RUNNING BACK TO CARB FROM THE RETERN LINE, AFTER IT'S EMPTEE IT DIES

By mark harding (Promoza) on Unrecorded Date: Edit

Dave are you for sure there are no vacuum leaks even at the crank seal the ones behind the clutch and also the flywheel of the motor that's why i dislike 2 strokes the vacuum will drive you nuts till you find it i have been there come to find out on my sled the gasket blew out that's between the engine hafts mite want to take wd40 and spry around to make sure it is all sealed tight and no leaks good luck

By david berger (Davidrrrd) on Unrecorded Date: Edit

ACTUALY MARK I DO BELEAVE THERS A POSABILITY OF A VACUME LEAK LIKE THE ONES YOUR DISCRIBEING!
HOWEVER HAVING CONVINCED MYSELF IT WAS A GOOD IDEA TO HAVE SUCH THINGS AS THAT FIXED I TOOK MY KAWASAKI440 FROM MY MAX II AND HAD A LOCALE GUY REPLACE SEALS,$148.0 WELL IT NEVER RAN AGAIN!
IT WAS NOT RUNNING SO I HAD TOO LEAVE IT HOME WHEN I LEFT FOR THE JULY 2002 HUMPHREY JAMBOREE!
LAITER I SPENT EVEN MORE $$ AT ANOTHER PLACE AND THEY DID NOTHING FOR ME, EXEPT LOUSE SOME PARTS AND TELL ME IT WAS BEOND HOPE ANYHOW,
I HAD TO BUY ANOTHER ENGINE!
NOPE I AINT FIXING SOMETHING THAT RUNS GREAT BUT JUST NEEDS A PUMP TO DO IT,

By mark harding (Promoza) on Unrecorded Date: Edit

hey dave i understand were you are comeing from so good luck getting to the bottom of the problum

By david berger (Davidrrrd) on Unrecorded Date: Edit

or bypassing this one, heh heh heh