3205 Rear Main Seal

jsoluna · #1 11-19-2016, 03:39 PM

A while back I resealed the front cover and installed a new water pump and front main seal on the Kawasaki FD620D. Not long after that, I developed a major oil leak at the rear of the engine. With the radiator and shrouding in place, it was difficult to tell exactly where it was coming from (as most crank seals can be) but I figured that it made sense that I had disturbed mounting of the crankshaft by removing it's front support and thus comprised the already marginal sealing of the original rear main seal.

After doing some ground engaging work and pushing brush piles around last week, I had sheared the fan blades on my hydro pump fan (skid plate coming soon!)

Since I had to remove the driveshaft I figured it was time to take the plunge and fix the oil leak as well.

It was insanely packed with oil and debris. It's surprising that it was charging and firing as well as it was with all the buildup on the ignition pulse coils and charging coil. A simple attack with brake clean didn't suffice so I had to pressure wash it. Of course, today the outside temps have dropped to half of what they were yesterday (thanks, Ohio!).

I just got the old seal out and it is certainly shot. Hard as a rock. Excited to get the Kawi back together and wanted to share some teardown pics. It can be done with the engine in the frame, it requires removing the radiator, coolant tank, fan shroud, lower shroud, and starter, and charging coil. I also removed the radiator fan to make access from the top down easier.

1500 hours and still going strong! These are some amazing engines. Crank is still nice and tight. Previous owner was terrible with maintenance. I bought it with an overheated engine and blown trans with no bearings left in the axles and a split carrier. Engine is still all original internals.

J-Mech · #2 11-19-2016, 04:03 PM

Good job!

Don't be so impressed, 1500 hours on a liquid cooled engine is no big deal. It had better last at least that long. I don't know what you mean by the crank is still tight. It better be. If it was loose, you wouldn't be bragging that it runs good. You can't tell if a crank or a bearing is worn by looking at the outside of an engine, or jerking on the crank with your hand. I've seen a few thrust bearings on cranks that were wore enough you could move the crank fore and aft with a bar or even by hand... but that was on manual trans engines. Still... most people would never be able to feel even .020" play, or know if it was normal. Not busting your balls, just telling you some things you should know.

jsoluna · #3 11-19-2016, 05:45 PM

Never owned a small liquid cooled engine, I just assumed with its lack of maintenance and overheating that it was doing well for 1500 hours.

J-Mech · #4 11-19-2016, 06:29 PM

Well, let's do it this way. If it was a motorcycle engine, which is a good comparison, it would be equal to about 75,000 miles. I would hope it would run at least that long. Being liquid cooled makes a big difference in engine life. But, just like any other engine, overheating it will kill it.

Oak · #5 11-19-2016, 08:50 PM

[QUOTE=J-Mech;399996]Good job!

or jerking on the crank with your hand.

I'll keep that in mind J.

J-Mech · #6 11-19-2016, 09:28 PM

I think it's good to get a second opinion. I usually let my wife jerk my crank just to be sure that it's in good working order.

ol'George · #7 11-20-2016, 06:55 AM

Quote:

Originally Posted by J-Mech

I think it's good to get a second opinion. I usually let my wife jerk my crank just to be sure that it's in good working order.

Carefull, -----they have a habit of comparing on social media.

Knew of a guy who sent his wife to the hwd store to get a box of 1/2" diameter lag screws, 8" long for a wood project he was working on.
She returned with a box of 1/2" dia. 3 " long lag screws.
He said they were way too short, she said noooo- for years you've been telling me that length is 8"

Sam Mac · #8 11-20-2016, 09:25 AM

[QUOTE=Oak;400022]

Quote:

Originally Posted by J-Mech

Good job!

or jerking on the crank with your hand.

I'll keep that in mind J.

Quote:

Originally Posted by J-Mech

I think it's good to get a second opinion. I usually let my wife jerk my crank just to be sure that it's in good working order.

Quote:

Originally Posted by ol'George

Carefull, -----they have a habit of comparing on social media.

Knew of a guy who sent his wife to the hwd store to get a box of 1/2" diameter lag screws, 8" long for a wood project he was working on.
She returned with a box of 1/2" dia. 3 " long lag screws.
He said they were way too short, she said noooo- for years you've been telling me that length is 8"

You guys are getting into a risky area.