Motor transplant in Craftsman lawn tractor 18.5 HP B/S motor to an B/S 20 HP motor.....

[mrbreezeet1]

On the phone with him now! And he's trying to tighten the pulley on to the motor. But the shaft motor is turning too.
{He has an Impact, but don't have the tractor high enough ATM. If he jacks it up high enough to get the lmpact in there. that should zip it down then. correct?

 

[ripcord]

Probably it can be swapped over. The oil fill tube usually has an o-ring seal at the bottom and just pulls out once unbolted.

 

[mrbreezeet1]

To reword what I said:
You arent using the old motor.. or old carb??

if you were you could convert to electric fuel pump no problem.

with the new motor/carb that was setup as gravity fed I am uncertain.
but plenty more people here that know more than I ever will about these types of things..

OK, I understand!

 

[mrbreezeet1]

Probably it can be swapped over. The oil fill tube usually has an O-ring seal at the bottom and just pulls out once unbolted.

We are going to try to do that then. ^^^^^^^^^^^^^^^^^^^^^.
If I may get ahead of the game a bit here, if we do go to an electric pump, do I just power the pump with 12V+ from a key on power source, or is there some type of oil pressure switch I need to power the pump through, so that the pump shuts down without oil pressure?

 

[ripcord]

It probably doesn't have a low oil pressure cutoff. I would just connect it to key on 12v. If you do install an electric pump, make sure to get the lowest pressure pump you can find to avoid carb flooding issues. 1 PSI would be enough.

 

[mrbreezeet1]

The choke\throttle linkage needs to be compatible. That has been the problem area when I have done an engine swap.

Understood! Turns out they were "plug and play" as was the case with the electrical connector!
Shaft diameter and length were the same too!

 

[mrbreezeet1]

Amazon.com

Says 2.5-4 PSI Inline Fuel Pump. So is the PSI on these pumps adjustable, or is that just average pressure? I don't see one anywhere with less pressure.​

 

[vwmaniaman]

Electric pump would have to be low pressure to keep from flooding the carb. I have an electric on an old VW with a carb that ony puts out 3-4 psi.

 

[mrbreezeet1]

Electric pump would have to be low pressure to keep from flooding the carb. I have an electric on an old VW with a carb that only puts out 3-4 psi.

Right, so how low are we talking? Ripcord says ~ 1 PSI the one I linked to says 2.5 to 4 PSI. I don't know if they are adjustable or if that is just an average pressure.
We are still going to try to swap the oil fill tube to use the pulse type pump, I'm just trying to plan ahead a bit here. My buddy gets disgusted pretty quick with things, so I'm just trying to make the job go as smoothly as I can.

 

[mrbreezeet1]

OK, I understand!

Yeah, So if we have to go Electric, we will use the old carb.

 

[Elkins45]

The newer ones take vacuum from off one of the valve covers to power the pump. Does the replacement engine have a small tube coming off the top of one of the valve covers?

See the black tube between the valve cover and fuel pump here? Does your new engine have one of those?

 

[mrbreezeet1]

The newer ones take vacuum from off one of the valve covers to power the pump. Does the replacement engine have a small tube coming off the top of one of the valve covers?

See the black tube between the valve cover and fuel pump here? Does your new engine have one of those?

View attachment 177951

Not sure? He's up in Pittsburgh, I'm Down in Wheeling WV area.
Is running off the valve cover better that the Oil fill/Dipstick?
I would rather use the Old Fuel pump, vers. going electric!
He was supposed to pull the covers and see lf he can swap oil fill tubes.
I just called him, but he's probably out in the garage, he didn't answer yet!

 

[Elkins45]

Not sure? He's up in Pittsburgh, I'm Down in Wheeling WV area.
Is running off the valve cover better that the Oil fill/Dipstick?
I would rather use the Old Fuel pump, vers. going electric!
He was supposed to pull the covers and see lf he can swap oil fill tubes.
I just called him, but he's probably out in the garage, he didn't answer yet!

The valve cover isn’t better. If he can swap the dipstick and make it work that’s the way to go.

 

[wag123]

I strongly recommend NOT using an electric fuel pump.
The mechanical fuel pump operates off of crankcase vacuum/pressure pulses. This can be picked-up anywhere on the crankcase (or valve covers) that isn't under the oil level. All B&S twins have provisions for it. Look up the parts breakdown for the specific 20hp engine to find the provision on that engine. Most of the newer engines take it off of the valve cover. You can drill a hole in the top of one of the valve covers such that a piece of hose will fit snugly and run it to the fuel pump, which can be mounted anywhere that is convenient.

 

[mrbreezeet1]

Well, I wanted to thank everyone for their insights and advise and or Ideas and being part of our think tank!
Oil fill tube switched right over! Was able to install the old fuel pump! We/he used the old cover simply because the old cover had a prevision to attach the fuel pump. He just needs to put the new blades on that he has and put the deck back on, and he's ready to rock!
Thanks again to all!

 

[mrbreezeet1]

Well, I wanted to thank everyone for their insights and advise and or Ideas and being part of our think tank!
Oil fill tube switched right over! Was able to install the old fuel pump! We/he used the old cover simply because the old cover had a prevision to attach the fuel pump. He just needs to put the new blades on that he has and put the deck back on, and he's ready to rock!
Thanks again to all!

Well he ran into another issue, I know it might be hard to fix over the internet but here goes.
He has very little drive or reverse engagement. He must have something not back together right.
He had to remove one of the idler pullies to get to one of the motor mounting bolts or nuts.
Here is a clue, when he presses the brake/clutch pedal, it goes most of the way to the "floor" and also has a metal to metal sound and feel. If he lets the mower run for a while, it will creep along in drive, albeit very slowly.
I know it may be hard to fix online, but does anyone have any ideas?

 

[mrbreezeet1]

Question, do these tractors use a reeves drive system to vary the speed of the mower? Pretty sure they do.

 

[ripcord]

Is the new engine's pulley the same diameter as the original? If it is smaller, the belt may now be too long. He also may have a belt routing issue or a tension-er might be miss-adjusted.

 

[mrbreezeet1]

Is the new engine's pulley the same diameter as the original? If it is smaller, the belt may now be too long. He also may have a belt routing issue or a tension-er might be miss-adjusted.

He said it was all the same. I've been searching and searching for a good picture of the belt routing!
Would taking the Idler pulley off disturb #'s 22, 24, 19, 252, and 25 in this picture? We thought maybe something may have become undone there.
Belt routing issue is a possibility!

 

[ripcord]

Both blade engagement and transaxle operation are effected?