Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

japper

16hp Vanguard V Twin broken pushrod

Recommended Posts

japper

I am not a small engine guru and have posted this question in hopes of gaining some understanding about the following problem from some of you knowledgable folks on this forum...

I have finally gotten around to working on a Deutz Allis 1616 tractor that I bought from a local hardware store a couple of years ago.

This tractor is equipped with a 16hp Vanguard V Twin (Model#: 303777.

and the guy at the hardware store said that it stumped his tech as he couldn't get it started.

I had to work my way through getting it to turn over as it had some wiring problems but once I could turn it over, I was geting an amazing amount of loud backfire through the carburator.

Upon closer inspection, I found that I have a broken aluminum exhaust pushrod on one of the cylinders. (which explains the carb backfire)

By the way, I did a compression test before I found the bad pushrod and that cylinder had ~ 118 PSI while the other cylinder has ~ 122 PSI, which I am guessing seems normal with nothing to be concerned about, right?

A couple of questions:

1. The pushrod looked like it bent before it broke, what would cause this to happen and is there anything else I should check?

2. Does anyone have some tips on how to adjust the rocker arm once I install a new pushrod?

I am planning to get a new pushrod tomorrow and wanted to make sure that there isn't something else that I may need...

Once this issue is resolved, I have to figure out why I am not getting fuel to the carb, but first things first...

Thanks

Share this post


Link to post
Share on other sites
BLT

Generally but not always the case a push rod will bend from a stuck valve caused by overheating due to debris in the the head fins. Overhead valve engines are more prone to over heating in the head area then L head engines. That is just one thought.

Share this post


Link to post
Share on other sites
japper

Thanks BLT

How can I verify if the valve is stuck, can I manually put pressure on it to see if it will move?

If the valve is stuck, does that mean it should be replaced or can it by cleaned up with some WD40 or something?

thanks again

Share this post


Link to post
Share on other sites
JimDk

I repaired a Vanguard for a friend that had that problem. I had zero experience with that engine, so I called my go-to guy for newer engine advise. He told me that the broken push rod was caused by too much clearance, which caused the rod to jump off the rocker and jam in the channel.

He advised me to set the clearance at .000" cold. With the piston at TDC on the compression stroke, turn the adjuster down until the push rod still turns but there is no up and down movement. He told me that the factory specs are for .006" clearance, but with wear and heating this is too much clearance. The aluminum cylinder has much more mass than the push rod and expands more.

I set all 4 valves using his advise. The tractor is still mowing grass several years later.

Share this post


Link to post
Share on other sites
japper

I had to order a new pushrod and got it on Friday and installed in this afternoon... The engine starts and runs for a few seconds on a prime but then dies. I put new gas in the tank but it must not be getting fuel.

What sort of things should I check for that would cause no fuel delivery on the 16hp vanguard?

Thanks again

Share this post


Link to post
Share on other sites
Gordan

The solenoid is at the bottom of the main jet. When you say "prime", what do you mean - where and how are you priming? If the solenoid clicks when you turn the key to on, it's likely good. If it doesn't, and there's voltage on its leads, it's bad.

The pump is a little mechanical diaphragm jobbie that has a vacuum or impulse line to it and input/output fuel lines - depends on how they're set up, my Vanguard is a propane engine so it has none of these doodads. They typically incorporate a diaphragm and a check valve. If you disconnect the fuel line from the carb and fuel runs from it when you crank, and there's no gasoline in your oil (smell the dipstick), it's likely to be good. Some people replace these with electric fuel pumps.

Share this post


Link to post
Share on other sites
japper

Thanks Gordan.

By priming, I meant squirting some gas into the carburetor...

I have been working on this tractor on an off as time allows and after your post I pulled the solenoid off and noticed that the wire had some frayed insulation.

I pulled the shroud and found a mouse condominium with a bunch of debris packed in tight under the shroud. I cleaned this all out and replaced the fuel solenoid off a spare 12.5 HP vanguard that I have

(this 12.5 HP engine is locked up the but solenoid worked on this one).

As far as I can tell, the power to this solenoid comes from the ignition switch on a red/white wire. I noticed that this can be a little intermittent as looking at this wire with my trouble light.

It does not always have juice when the switch is in the "ON position" but sometimes comes on in the "START position" and when this happens, then it will usually be on in the "ON position" right after releasing the key from the "START position".

I cleaned the contacts on the ignition switch and the connector contacts and tested the ignition switch with an ohmmeter but I need to look at the voltage with a meter to know more.

I guess my next step is to make sure there is voltage on this solenoid in the ignition switch run & start positions and then follow that through to the upper/lower harness connector to the fuel solenoid ...

By the way, I don't ever recall hearing this solenoid click when the ignition was turned on with the 12.5 HP mower when it was operational.

Is this always an audible click?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×