All right goo-rues of the long tail. I've got a 20hp briggs that is running like crap as of now. Out of the water it runs fine, but when you put a load on it ,it runs like the motor is going to come off the frame. I'm pretty sure that it's a fuel problem b/c i got it to run pretty good on 1/2 choke. Where should i start, Fuel line , carb , .....

Fuel Filter, Air Filter? ck them..

I would "tune it up" new plugs, filters, fresh gas....

Had same problem on two, this fixed up both...

Water in Gas......
Dirty Carb....

+1 on what each of these guys said.

Routine general maintaince should clear up the problem.


Gee

Sell, yours, and buy mine

J/K I agree with the others, tune that bitch up and depending on the age of the fuel line, you might want to change it out. You can do all that and buy a bag of chips for about $40.00 or less.

Good Luck

x2 on de "tune up"

don't forget to check your valve lash.

Also check for "dead cylinder" - out of water they will run great
on a single cylinder - try removing one spark plug wire at a time - if
there is no change on one then dies when other is removed - you have
a "dead cylinder" - compression test will tell if it is electrical or
mechanical....

Allright., after some torubble shooting and a compression check i decided to tear down my engine a bit and do a bit of bringing the old back to life. I had 65psi in both cylenders. I lapped my valves and changed my head gaskets. Tightened everything up and checked my compression again and i have 130 on one side and 170 on the other..... Could it be that my exhaust valve isn't opening properly on the high side? What are my tolerances on my exhaust and intake valve on this engine? i want to say .003 and .004 but i don't remember. What should my compression run? any help would be appreciated.

Google is my friend.

http://wiki.answers.com/Q/How_much_comp ... _hp_engine

the intrawebs tellz me 130lbs or higher is da bestest (if its a briggs motor)

but obviously the older the motor the lower the compression. so 120 ish IMO would be good. If that doesnt work I suggest looking on the http://www.briggsandstratton.com/ website and that should be able to help you if you put in your model number N crap.


Hope this helped. sorry your having troubles.


Gee

went back and checked my work. My intake push rod on the low side wasn't in it's seat on the rocker arm. My intake valve wasn't seating all the way . Fixed it and now have 175psi on both cylenders.....Going run it Sat.

wow, 175 is huge! I'm glad you figured out what was causing the low pressure on the one side tho.

Success !!! Went run it this yesturday afternoon. Much more power and ran great. Got to get another boat to put it on. My tunnel hull's transom is too tall. Might try adding a little adjustment plate to the end of mine to be able to adjust it more than the factory.