16 HP Opposed Twin Question and Service Manual

I have a B&S Engine (401417-0011-01-80052012) that is not currently running. I am trying to get it going. A little backstory is that this motor was on a 'kit' 3 wheeler type of ranch buggy from back in the 70's. It's a two seater with saddlebags and has the capacity to carry some small cargo that you might need on a ranch way before the days of UTV's. Anyway, I have it in all original condition, and it was purchased by my grandfather. A family member recently took the entire 'bike' to a shop. They shop owner spent a great deal of time telling us that it was really cool and fawned all over the item before taking it in to see if he could get it running. The next day he called and said "It has low compression, we can't get parts for it, but I'll give you 500 bucks for it as is if you want to just leave it".

Anyway, I have the thing myself and I need to verify if it in fact has low compression. My suspicion is that it's fine. I have rebuilt all manner of small engines and am equipped to handle this restoration.

1.) I need to get my compression tester, and I know how to use that, but since this motor has been sitting for so long (YEARS), how should I test the compression? I want to put oil in the cylinder first....but is that advised?

2.) What compression numbers am I looking for? I think the number itself is not quite as important as the two cylinders being close to each other. Either way, I need some guidance on that.

3.) In reference to the above question...Does anyone have a service manual in PDF form for this particular motor? I am usually pretty good at finding these online, but I have not located a service or repair manual...just the operators manual and IPL.

Thank you for all of your help!

Someone on here has quite a few Briggs Manuals in PDF form........

I have a few but they are not sharable and if I would I would be in deep schitt with Briggs....

Tinker and Boo Boo post links all the time for Briggs........

You should be looking for at least 65 PSI minimum...... I don't remember if they had a comp release or not... It's been a while since I worked on one ...........

You can google like this... Briggs then your number and type code then Jack's small engine repapair will pop up click on that one and it will have diagrams that can be blown up......

If I a correct this manual should help you out.
https://drive.google.com/file/d/0B6NaqjIxWV1ybHphbUNTQUNNR2s/view

If this guy is offering you $500 for a 28 year old engine, that he says you can get parts for, I’m willing to bet the engine has good compression. What I would do is squirt some very light oil into the cylinders and spin it over a dozen times with the plugs out. Then install the plugs, spray some carb cleaner into the carb and see if it will fire and run. If you can’t get it to run, many of the auto parts stores offer free loaner tools. I would make a few calls and see what what is available in your area. I would be looking for a PSI of over 110, but would accept 90. Just my opinion.

Look for my reply on other forum. Compression of 110 is very unlikely given passive compression release except it might with oil in cylinder, not dry.

Walt Conner

Thirty years ago, when that engine was built, most mechanics went by a common practice on Briggs L-Head engines was to look for a compression reading of 125-140 PSI. These opposed engines did not have a compression release and at that time leak down tests were not a common practice. With the age of that engine I would be looking for a compression of 110 PSI. If doing a compression test you should first do the test dry, to determine abase line and then add a little oil to the cylinder if the PSI is low and you wanted to determine if the cause is rings, gasket or valves. Most garage mechanics do not have or know how to use a leakdown tester and on engines with no compression release, a compression will give you a good starting point on non running engines.

Actually these engines along with most if not all B&S flat head engines of any size (and some OHV engines) have what I call a "Passive" compression release which holds the intake valve slightly open well into the compression stroke also known as the easy spin cam grind or easy start, forget which.

Walt Conner

I never got around to checking compression. However, I squirted some oil in the cylinders and when I spun the motor around, I saw a chocolatey looking soup splash up. So....I pulled the head on the rear most cylinder on my machine. Gray soupey water/oil came out.

Not good. What is worse is that the cylinder wall is HEAVILY scored. The block is aluminum.

Do you think you fine people can walk me through what I need to do next? I would like to repower this. Briggs does not have a direct replacement. I am open to Honda, Kohler, etc if I can find a direct replacement.

What would you guys do? I have replaced engines with 'short blocks' before. Most of the motors like this I see on ebay have no pistons or anything in them. It's a bit of a complete start over.

I found this on ebay, but I need something that everything will just bolt back onto. Not sure what pistons I need for this or if I need a new crank to fit, or what exactly will swap over.
https://www.ebay.com/itm/Briggs-422...=item1cc39f12c5:g:d7YAAOSwkERcET0F:rk:22:pf:0


What do you all suggest now?:frown:

agdodge4x4 said:

I never got around to checking compression. However, I squirted some oil in the cylinders and when I spun the motor around, I saw a chocolatey looking soup splash up. So....I pulled the head on the rear most cylinder on my machine. Gray soupey water/oil came out.

Not good. What is worse is that the cylinder wall is HEAVILY scored. The block is aluminum.

Do you think you fine people can walk me through what I need to do next? I would like to repower this. Briggs does not have a direct replacement. I am open to Honda, Kohler, etc if I can find a direct replacement.

What would you guys do? I have replaced engines with 'short blocks' before. Most of the motors like this I see on ebay have no pistons or anything in them. It's a bit of a complete start over.

I found this on ebay, but I need something that everything will just bolt back onto. Not sure what pistons I need for this or if I need a new crank to fit, or what exactly will swap over.
https://www.ebay.com/itm/Briggs-422...=item1cc39f12c5:g:d7YAAOSwkERcET0F:rk:22:pf:0


What do you all suggest now?:frown:

Click to expand...

I'll try to find a briggs replacement for you , There is a Briggs engine that will fit your application.... Put a magnet inside the cylinder.... If it sticks then you have a cast iron sleeve pressed into the aluminum block ...........

Let us know Mon Ami ~!~!

I'd get on Craigs list or similar site and look for a riding mower with an engine close to what you have, might get lucky and buy the whole thing for a couple hundred. Overhauling that motor might run into serious money and those aluminum cylinders are sometimes a real disappointment on rebuilds.