(800) 853-2651
SHOP NOW

18 hp briggs intek?

Geo-TH,In

Geo-TH,In

Well-known Member
Helping a friend get his mower running. I think he has a bad cam. I put my 400 cca battery in mower. Starter won't spin motor over. Took spark plug out; motor spinns just fine. I checked exhaust valve and set it to .004. When I turn motor over by hand, shouldn't the exhaust valve open for a moment during the compression stroke, exhaust valve becomes the decompression valve? Well it doesn't. So, I decided to put spark plug in only half way allowing some compression to escape past the plug threads.

It spins over and starts just like it should.

I'm thinking it has a bad cam? Anyone have cam problems with the 18 hp single cylinder briggs? Anyone have experience changing the cam?

Any idea how to tighten spark plug while it's running?? Just a joke, OK?

I'm thinking Bubba may install a pet-cock valve like those on the old JD's?
George
 
Some of the large single cylinder engime have a built in decompression valve. It sounds like what ever opens it is not working .
 
Sounds like one of the ariens riders. The intek motors are usually decent. I believe they have an engine breakdown on the ariens website. If they dont check to see if any husqvarnas using the same motor. They build the riders for ariens. They're usually pretty good about diagrams too.
 
The exhaust vavle was very close to .007. I detect no movement on exhaust valve during compression like I did on my 13 hp honda. Something is wrong with cam that is responsible for decompression.

Any ideas how to fix without taking motor apart?
George
 
I have the same problem on my JD L130 mower. Someday I will adjust the exhaust valve (closer, not looser) to eliminate it, meanwhile just turning it over past compression by hand will get it spinning and it starts right up. Setting the exhaust valve too loose disables the compression release feature.
 
Paul, I totally agree, if too loose, decompression won't work. I have adjusted for than one engine. When they don't work, need to tighten up. But there is something wrong with decompression part of cam. Any ideas how to wake it up?
George
 
Briggs Intek engines require the piston be past top dead center and down 1/4 inch when exhaust valves is adjusted. If valves are adjusted with piston top dead center the compression release will not work.
 
On those single cylinder Briggs, Most of them used the profile of the cam for their compression release, and held the intake valve open for a bit on the compression stroke.

Try setting both valves to .003 with the piston about 1/2" down the cylinder on the power stroke and see how it cranks.

A worn out cam is not unheard of, I do recall about 4 years ago one MTD came in for valve adjustment three times three consecutive months before I realized it was the cam wearing out in it. Each time, I could adjust the valves and it would start well again.

If this is by chance one of the early V-twins, everything I said still applies. . .

This was probably due to poor maintenance, infrequent or no oil changes in the past.
 
on a 21 hp 2 cy piece of junk engine i had the same problem. 003, 004 both simply would not release compression. finally widen gaps and works like a charm. remove plugs, with screwdriver gently inserted into plug hole, rotate engine to tdc observing screwdriver and then slightly past to ensure all pressure is remove from springs and then adjusted. worked for me.
 

Good customer of mine had a cam issue... No adjustment either way would cure it... Its a EZ engine to work on nuttin to it once you get it in yer head to go after the cam...
 
HOBO,
Deffinately a bad cam. Parts store said it's a commom problem. Cam and gasket $150. Friend is going to buy a used mower and not fix this one.

Thanks to all.
George
 
Hello George Marsh,

Sometimes the compression release wears just out May be it is just stuck in the off position.

Guido.
 
You must log in or register to reply here.

Similar threads

R
23 hp kohler problem
Replies
7
Views
793
rrman61
R
R
Ford 8n - Backfire / Misfire
Replies
12
Views
541
Eman85
E
D
Ford 640 with high compression pistons
Replies
10
Views
627
RBnSC
RBnSC
H
Briggs and Straton engine troubles
2
Replies
24
Views
3K
stevieb49829
stevieb49829
D
Sticky valves?
Replies
8
Views
1K
Don B.
D
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top