18hp Max IV cutting out on steep hills

[smithder]

I've read other folks with this issue but I'm not sure what's the best solution. My machine will hesitate when given full throttle to come up a short steep hill like a ditch. I think an electric fuel pump would do it but though I would try and fix it without the added saftey concern first.

What worked for you?

[Bazooo guy]

If the engine is starving for fuel because the fuel tank is lower than the carb on an incline than a fuel pump will help.
Carbs with floats are designed to run on level ground.....fuel injection has solved that in the offroad world.
A pumper carb will operate at any angle (chain saws & weed wackers and older snowmobiles and dirt bikes use them)
I think your problem isnt related to fuel starvation on a short hill at wot....it could be ignition timing or just in need of a tuneup.

[amphibious drew]

I too have a 18 vanguard, but its in an attex and I just put it in new last summer/fall. I have noticed the same issue, but only uphill and at wot. When going down hill I never had an issue. I think its just the fuel getting away from the jets. I've heard of people putting a low flow electric fuel pump on to help solve the problem. I would only use it if I were going up a steep hill. Running it at all times is a potential fire hazard from what I've read.

[mudNmallards]

Just food for thought

I always use the process of elimination method to isolate a problem before I apply a fix that may not address the problem and waste money.

I question whether a pump would address your problem because (in theory depending on the type of carb you are using) during the load moment the engine vacuum is pulling the fuel from whats in the carb. A fuel pump is on the supply side so unless it started up the hill and during the process got fuel starved ( running out of gas in the carb proper) I wouldnt think the supply side would be the root problem.

Have you considered and eliminated maybe a timing issue or exhaust valve cause?

It might also be the angle of the hill in relation to the HP, drive train load or maybe a mis adjusted clutch system could be causing the engine to simply bog?

[amphibious drew]

Just food for thought

I always use the process of elimination method to isolate a problem before I apply a fix that may not address the problem and waste money.

I question whether a pump would address your problem because (in theory depending on the type of carb you are using) during the load moment the engine vacuum is pulling the fuel from whats in the carb. A fuel pump is on the supply side so unless it started up the hill and during the process got fuel starved ( running out of gas in the carb proper) I wouldnt think the supply side would be the root problem.

Have you considered and eliminated maybe a timing issue or exhaust valve cause?

It might also be the angle of the hill in relation to the HP, drive train load or maybe a mis adjusted clutch system could be causing the engine to simply bog?

Nope they run out of gas in the carb. some if the argo guys solved this with the fuel pump thing.

[mudNmallards]

If thats the case then I would go the in tank pump route with the lowest possible pick up with higher pressure and a fuel return line along with a split filter. That would put any fuel starvation issue to rest permanently.

[jpswift1]

If thats the case then I would go the in tank pump route with the lowest possible pick up with higher pressure and a fuel return line along with a split filter. That would put any fuel starvation issue to rest permanently.

The Argo guys solved this issue like Drew said with an electric fuel pump. It's a low PSI in-line unit, not one that goes in the tank.

[smithder]

Anyone know what in line pump folks are using. It did it today trying to climb out of a lake on a steep bank. As soon as you go to wide open throttle she has to think about it for a couple seconds before giving all the beans.

[mudNmallards]

The Argo guys solved this issue like Drew said with an electric fuel pump. It's a low PSI in-line unit, not one that goes in the tank.

I dont doubt thats adequate but here is what drove my answer.

I've been looking at all kinds of youtube videos and watching what these things do to make a purchase decision.

2 that stuck out in my mind were the almost vertical ( about 80 degrees) climbing logs and going uphill- that requires a pressurized system. No doubt about it.

The other is from my secondary area of experience- pump systems. I doubt it would be a big issue on machines as small as these but its simple physics when computing pump head curves. Its easier and more reliable to blow rather than suck. ( or in pump terms better to work against pressure head rather than suction head)

So, in any given application, its simply better all the way around to move the pump closer to the reservoir rather than further inline. A simple test is to take about 10' of tubing and pretend its a straw. Suck out of a cup then blow a mouthfull into a different cup. See which is easier. Pumps are no different.

[amphibious drew]

I dont doubt thats adequate but here is what drove my answer.

I've been looking at all kinds of youtube videos and watching what these things do to make a purchase decision.

2 that stuck out in my mind were the almost vertical ( about 80 degrees) climbing logs and going uphill- that requires a pressurized system. No doubt about it.

The other is from my secondary area of experience- pump systems. I doubt it would be a big issue on machines as small as these but its simple physics when computing pump head curves. Its easier and more reliable to blow rather than suck. ( or in pump terms better to work against pressure head rather than suction head)

So, in any given application, its simply better all the way around to move the pump closer to the reservoir rather than further inline. A simple test is to take about 10' of tubing and pretend its a straw. Suck out of a cup then blow a mouthfull into a different cup. See which is easier. Pumps are no different.

Too much fuel causes the carb to overflow and the engine to catch fire. Yes it does and has happened. The extra pump is only to help fill the carb at extream forward angles. The vacuum fuel pump in the back of the machine provides more than enough fuel for any other maneuver. In fact, I know a tractor pulling guy that used to run 3 oh160s off a single vacuum pump with no starvation issues. By running an electric fuel pump all the time, the float overflows fuel out the air intake onto the manifold which is hot and hence catches the machine on fire. Too much fuel is way worse than too little. I would much rather stall than have to build a replacement machine.

Also, I am pretty sure Briggs knows how to time their engines properly from the factory. in another post you mentioned you know nothing of small engines. It may more helpful if suggestions based only on theory and not practical experience are not stated as facts. There are many people on here with experience and even engineering degrees that have helped solve newbie problems for many years.

[hydromike]

Anyone know what in line pump folks are using. It did it today trying to climb out of a lake on a steep bank. As soon as you go to wide open throttle she has to think about it for a couple seconds before giving all the beans.

I think folks are running a few different styles of the 12V, low psi pumps. Here's an example of an ebay listing with one that'd work for you.

Fuel Pump, Electric, Carburetor, Domestic, 4-7 psi., 35 gph., Each (084041000120) | eBay

Mounting the pump low, and toward the back of the machine has worked on the two machines (both Kubota engines) I've run these on. I've had no issues with too much pressure floating the needle off the seat, and I don't use a pressure regulator. Mine are both gravity fed from the fuel tank (plenty of pressure head) and only need to push about a foot to the carb in each application. Make sure to run an inline filter before each pump to make sure gunk doesn't get transmitted to the pump.

[smithder]

I wonder hw much PSI is required. Here is a 1-3 psi pump...

Low Pressure Electric Fuel Pump gas,diesel, 1-3 psi 12 VOLTS | eBay

Maybe less chance of supplying too much fuel.

Do you keep the vacuum fuel pump in place or remove it?

[hydromike]

I think that pump would work just fine. I remove the vacuum pump entirely, and just feed the carb inlet from the output on the pump.