1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!

Mastiffman

Member
Joined
Jun 8, 2015
Threads
1
Messages
16
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
Good day fellas!

I have a Kaw FC420V that needs a rod which I'm getting ready to replace and I'm curious if I can use a Rod from any FC420V or does it have match the last 4 revision(?) letters of the model. In this case BS02.

I can't seem to find any used ones on the bay. I would rather not drop a full $65+ on a new Rod if not a full rebuild of the engine. Just going to replace the Rod if the crank journal is fine as well as de-carbon it and do a valve and gov/carb adjust (Surges at idle).

Thanks in advance.
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
64
Messages
24,647
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
Normally not the BS02 describes the variation from standard.
Usually this will be things like a different crank end, different filters or even just decals on the blower housing.
My parts list down here shows 13251 for all engines.
If there has been an upgrade to a part, kawakasi give is a suffex , generally a letter and number shown this 13215-A1.
FWIW I can not find a FC420v-BS02 listed. the closest is FC420V-S02
 

Mastiffman

Member
Joined
Jun 8, 2015
Threads
1
Messages
16
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
Gotcha.

Yes, the Only part that I've seen with a variation the 13251 is an a after it and that's an undersized for crank rod journal correction.

Okay, so 13251 will fit all of the FC420v's That's good. That opens up my options quite a bit. I would assume that the S02 and BS02 would be the same being that the site that I'm looking it up on which is scag oem parts O c o m... And it's not showing an xS02 for any other revision of the FC420V from -Axxx through -Kxxx.

Thanks a ton for the reply and info! Great site!
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
64
Messages
24,647
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
I get into the kawakasi portal via either one of my wholesalers.
One goes to the USA portal via the Australian one and the other connects directly to the USA site.
AFAIK Joe Public can also access kawakasi direct if they have a USA or Canada url
 

Mastiffman

Member
Joined
Jun 8, 2015
Threads
1
Messages
16
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
Would that be the best place to get a new rod?

Also, are these rods aluminum or steel? If I have a knock are the chance high that I'd need a crank as well? I know the only way to really tell is to check the rod journal on the crank with a Mic.

What's your experience with it though? I'm not looking to fully rebuild the engine.
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
64
Messages
24,647
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
My opinion is to open it up and have a look before you do anything.
It could be a large number of things and you won't know till you have a look .
If you don't have a manual they are available from here http://www.mymowerparts.com/pdf/Kawasaki-Service-and-Repair-Manuals/.
I run a repair business so I get them through my trade suppliers but expect to pay more than you think, Kwaka parts are expensive which is why you pull it down first.
Then if it needs machining or more work than you are comfortable with you can sell it as is.
There are lots of backyard mechanics who will be happy to pay a reasonable amount for a dead engine that they can repair and in many cases these people will have a source of cheaper parts so you won't get value for the new parts you have bought.
 

Mastiffman

Member
Joined
Jun 8, 2015
Threads
1
Messages
16
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
Oh I hear ya. I was just preparing myself for the possibilities of what could be going on. Wisdom has taught me to pull the trigger to fast on purchases until you know what the problem is.

The engine runs great overall and it's had this slight knock for the last few years. It would make sense to pay double the shipping on a crank and rod if I bought the rod without pull the oil pan and micing the rod journals first. Which is the next step for me.

I'd be better off waiting to see what the issue is and then buying a used crank and rod/ piston set of the bay from a low hour well maintained engine.


That's the repair manual for FC420V? Thanks for that. I will definitely need that when reassembling it.
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
64
Messages
24,647
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
The kwaka manuals are fairly good.
The JD kwaka manual is even better but a lot more expensive than a free pdf download.
If you were running on premium fuel the knock could have been a combustion knock and not a loose rod.
Usually the rods are really good.
What gives most problems with singles is the counter balance mechanism.
The rod is shorter and turns a shorter arc so wears more and the bolt holding the 2 halves on Briggs & Kohler engines is what usually gives way first.
Got a lot with a good crank and a counterweigh through the side of the block.
 

Mastiffman

Member
Joined
Jun 8, 2015
Threads
1
Messages
16
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
That's good to hear on the manuals. And very crazy about the crank and counterweights through the block. Yikes. Seems like I;ve been lucky for this engine being a 1988 SW52-13BV. smh
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
64
Messages
24,647
  • / 1988 Scag w/ Kaw FC420v-BS02 and slight knock but runs great!
Near 20 years out of a mower engine is doing well.
So fair to say that engine owes you nothing.
Mower engines are fairly robust when used within specs but no noe can properly test or simulate years of use and the most complicated part of engine design is vibrations.
And vibrations is what does the damage.
 
Top