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View Full Version : Diary of my early 4160 rebuild.


catamount
05-20-2013, 11:02 AM
I bought this boat last year. I was never able to get a really healthy idle until 900 RPM. I know it should be happy purring along at 600 RPM, the timing is spot on and all signs pointed to the carb. Visually, it was full of carbon deposits on the choke plate and just looked neglected.

I am hoping that these photos may help someone in the future, if only to provide a visual reference to what goes where. This is my first time rebuilding a four barrel, and I've only rebuilt motorcycle carbs before this. I am learning as I go here.

This is my carb, Holley 4160 list 50419.

As I understand it, the number under the list details when the carb was built. The 297th day of 1986 in this case. I'm not entirely sure if that's true or an old wives tale.

http://i.imgur.com/3ofE6qB.jpg

Holley's site provides a great reference for figuring out which kit you need. For my carb they spec'd the 703-29 rebuild kit. Amazon had the best price for me, $36 with free 2-day Prime shipping.

http://i.imgur.com/G9E7iRS.jpg

Anyone with a pre-1992 4160 should also consider ordering Holley part 125-500: Power Valve Check Ball Kit. This kit updates the old 4160s to include backfire protection - no more losing your power valve if your engine suffers a backfire. $14 on Amazon. Thank you thatsmrmastercraft (http://www.mastercraft.com/teamtalk/showpost.php?p=840560&postcount=4)!

http://ecx.images-amazon.com/images/I/119h470ZI8L.jpg

http://www.amazon.com/dp/B00029JAPU/ref=pe_309540_26725410_item

Suggestion, take a ton of pictures of the small assemblies as you take them apart. This is the choke assembly.

http://i.imgur.com/dvtC6gh.jpg

One thing to clean is the choke breather screen. This provides some fresh air to the electric choke and keeps it from overheating. The screen on mine was completely full of carbon and I could not even blow through it. Take it out, soak it in carb cleaner and get it transparent again. A blocked breather will kill your choke.

http://i.imgur.com/RqJ9Umg.jpg

The bowls were pretty clean.

http://i.imgur.com/vP83drY.jpg

After removing some of the easy things, I gave the body a long dunk in my $70 Harbor Freight ultrasonic cleaner. I turned it every few minutes and after the initial hour or so I'll drain the dirty solution and rinse the parts with water.

Later, before assembly I'll run them through and rinse them again.

I have found this cleaner to be much more effective than the carb cleaner soaks I used to give my dirty carb parts.

http://i.imgur.com/OPjBlxX.jpg

This thing works wonders, and I use it all the time with motorcycle parts. My solution is 1 part Simple Green and 3 parts water. Turn it on and watch the carbon deposits break up and float away.

http://i.imgur.com/TrO0C4J.jpg

That solution was pretty much clear when I started.

http://i.imgur.com/ApjU6V2.jpg

The cleaner has a heater, and helps soften up the old gasket material.

http://i.imgur.com/1JCx2kh.jpg

At this point, I was pretty certain of at least one problem that was causing my rough low idle. A major vacuum leak -- the primate throttle plates were not snapping fully closed. They would close with some assistance, but they were binding due to "gunk".

http://i.imgur.com/A0UBDmU.jpg

The plates would seal up nicely with a little assistance, but they should completely close off without additional assistance (I mean, the return spring should be enough to do the job).

http://i.imgur.com/f16uuxb.jpg

By using a zip-tie, you can get the plate assemblies to stay open while they soak. Deposits have probably built up where they make contact with the throats.

http://i.imgur.com/hGJ2tKF.jpg

Soaking the body and cleaning the throats did not fully solve the problem, so I knew I would have to remove the primate throttle plates and remove the bore to clean out any deposits that could be causing the friction which was preventing a full close.

These brass screws had to come out in order to remove the plates (so I could slide the shaft out and clean the bores).

http://i.imgur.com/NiqA4NP.jpg

Of course, one of the 4 brass screws snapped off. What I wish I knew then, was that the brass screws are "staked" in place which means the ends are mushroomed out to prevent them from ever working themselves lose and finding their way into your cylinders. Of course, this makes them difficult to remove if you did not know this in the first place!

http://i.imgur.com/njdKKWA.jpg

Holley provides a great instruction document here for removing and replacing your throttle blades, should anyone encounter this in the future: http://www.holley.com/data/Products/Technical/199R9978rev.pdf. I wish I would've found that before I snapped the screw, as it calls for filing off the far end of the screw before attempting to unscrew it. Oh well!

With some careful drilling and the help of an 8-32 tap, I got the old screw out of there and cleaned up the threads. I found a pack of new brass screws on eBay and now I just have to wait for them to arrive.

In the meantime, I took the shaft to my polisher and shined up the bearing surfaces on the shaft. I also took a bore brush from my gun cleaning kit and ran it through the throttle body to get any remaining deposits out of there. The assembly snaps shut now.

http://i.imgur.com/Uf4aV2C.jpg

Now... the wait for parts to arrive. To be continued!

d2jp
05-20-2013, 09:14 PM
Thanks for the thread, I'm sure I will be here one day. If you wanna see your ultrasonic really clean, replace the Simple Green with Totally Awesome.

catamount
05-24-2013, 11:52 AM
The rebuild continues. The finish on the bowls looked terrible so I came up with a quick way to return them to bare aluminum. I know it will oxidize eventually, but at least they look "clean" again.

Secondary bowl before.

http://i.imgur.com/qybL9IO.jpg

Once all of the bits were removed, I put them in a bath of 5 parts water to 1 part CLR. Let them soak for 15 - 20 minutes and then took some steel wool to them. A wire brush on a dremel helped knock down the really ugly spots.

Secondary bowl after.

http://i.imgur.com/o02l55G.jpg

Primary bowl after.

http://i.imgur.com/r9IhSNM.jpg

Meanwhile, I soaked the main jets in carb cleaner and then ran them through my ultrasonic.

http://i.imgur.com/dlmeYxV.jpg

The new power valve also went in. My original PV was 2.5. The PV Holley sent in the marine rebuild kit was 5.0. I'm going to give it a shot and see how it runs. The 2.5 is still useable so I can always throw it back in if the 5.0 doesn't feel right.

http://i.imgur.com/89fBD2f.jpg

The old gasket was nearly impossible to remove from most of the parts. I used aerosol gasket remover to loosen it. It still took some time with a wire wheel on a dremel to get the parts back to bare metal.

Primary bowl before.

http://i.imgur.com/vP83drY.jpg

Primary bowl with the new needle & seat, and float set to parallel.

http://i.imgur.com/lPopA3s.jpg

Getting closer to the finish line now... fewer parts left on the table.

http://i.imgur.com/g4s21id.jpg

As mentioned earlier, Holley part 125-500 is an update for pre-1992 carbs without Power Valve protection. This $14 retrofit will protect your PV in the event of a backfire.

http://i.imgur.com/2Nx5CEy.jpg

It basically consists of a drill bit set to drill .300" deep, a spring, a ball bearing and a brass retainer.

http://i.imgur.com/u3y6lCs.jpg

The power valve orifice on the throttle body is drilled out to .300" deep, the spring inserted followed by the ball and the retainer. I will take a picture of the finished product tonight.

http://i.imgur.com/TcZQ0zP.jpg

Table Rocker
05-24-2013, 12:15 PM
Great pics/thread, well done!

JMann
05-24-2013, 02:25 PM
Thank you for taking the time to create this thread, I wish it was here a couple years ago when I was rebuilding mine.

catamount
05-28-2013, 11:03 AM
Here are the pictures from the Holley 125-500 installation. It's very simple, and will take all of 10 minutes.

First the passage is enlarged using the provided bit.

http://i.imgur.com/ScVY0Rc.jpg

Then the three components drop in the hole in this order: Spring (taper facing up), check ball and retaining ring (gently hammered in place).

http://i.imgur.com/yVkDnaQ.jpg

Final result.

http://i.imgur.com/RvaTbvs.jpg

Meanwhile, the brass throttle plate screws I ordered from eBay came in and I was able to remount the primary throttle plates following the instructions from Holley (located here (http://www.holley.com/data/Products/Technical/199R9978rev.pdf)).

http://i.imgur.com/Fw88RcS.jpg

http://i.imgur.com/4pM9gXd.jpg

As I was assembling the secondary, I thought I'd take a picture to remind that you will need a 5/32" clutch head driver to remove / replace your metering plate. Lots of people have just used a flathead screwdriver, but Ace hardware stocks these drivers for about $7 if you want to use the right tool for the job.

http://i.imgur.com/vWgaHni.jpg

It's all going back together now. After taking this picture, I realized that the choke assembly should go on last (after the secondary diaphragm). Oops. I hope to get this all back on the boat tonight.

http://i.imgur.com/k9RXPzD.jpg

catamount
05-29-2013, 11:00 AM
My final update.

http://i.imgur.com/xAThTAL.jpg

Once you get the carb back together, there are a few checks you need to make. One check is that the accelerator pump is not fully extended at WOT. Holley calls for a .015" clearance between the accelerator pump arm and the throttle actuator nut at WOT.

http://i.imgur.com/1TGSG3J.jpg

http://i.imgur.com/4Et9R6v.jpg

The intake manifold gasket had to be original.

http://i.imgur.com/9qh4kSr.jpg

Careful scraping with a shop vac next to me preventing bits from falling in. The carb spacer looked the same but was easier to deal with on my workbench. I cleaned that up and painted it while I had it off.

http://i.imgur.com/b73m0TG.jpg

Final step... check for leaks, adjust idle mixture screw(s) and go skiing.

http://i.imgur.com/YqGdCos.jpg

PS: Here is an amazing link for tuning / diagnosing any problems you might have with your 4160:

http://www.bob2000.com/carb.htm

TxsRiverRat
05-29-2013, 11:46 AM
This is one hell of a thread - nicely done... Way too complicated for me, but wow - this is great stuff.

johnlanguab
05-29-2013, 11:59 AM
Great work!

thatsmrmastercraft
05-29-2013, 12:19 PM
Nicely done catamount. Especially good to include the power valve kit.

cbryan70
05-29-2013, 12:41 PM
Nicely done catamount. Especially good to include the power valve kit.
When my carb needs a rebuild im shipping it to you with a case of beer.

thatsmrmastercraft
05-29-2013, 01:03 PM
When my carb needs a rebuild im shipping it to you with a case of beer.

http://forums.catholic.com/images/smilies/ani/ani_tiphat.gif

pbgbottle
06-02-2013, 11:08 PM
thanks for posting this ,i think i am going to rip mine apart also

catamount
06-03-2013, 01:15 PM
One last note, once you get the rebuilt carb back in place you can use baby "snot suckers" to prime your now empty bowls (as opposed to cranking the engine over and over again to get fuel in there).

Take off the breather and shoot some fuel up into the J tubes with one of these. Turn the key, and enjoy.

http://i.imgur.com/7nBAc15.jpg

thatsmrmastercraft
06-03-2013, 01:26 PM
One last note, once you get the rebuilt carb back in place you can use baby "snot suckers" to prime your now empty bowls (as opposed to cranking the engine over and over again to get fuel in there).

Take off the breather and shoot some fuel up into the J tubes with one of these. Turn the key, and enjoy.

http://i.imgur.com/7nBAc15.jpg

Good tip. Used to use "booger basters" to fill through the sight plug hole on automotive carbs but never thought to go through the J tubes. :toast:

pbgbottle
06-04-2013, 09:56 PM
just took my carb apart . don't have rebuild kit yet
but what did you do with this brass piece with oring does it come out ?
mine is wiggly but doesn't seem to come out . any info please. should it pull out ,not pull out ,be tight .not loose. and just replace the oring.

thanks

pbgbottle
06-04-2013, 09:59 PM
also you set both floats level right? have u ran yours yet .how does it run ?


,,,,,,,,,,,,,,,

catamount
06-04-2013, 10:30 PM
That brass piece comes out! It has an o-ring on both ends. However, my kit did not include the o-rings for it so be careful or replace them with o-rings you can find locally.

Mine runs great after the rebuild!

thatsmrmastercraft
06-05-2013, 01:37 AM
Replacing old o-rings is very important. If you didn't get them in your rebuild kit, either they missed putting them in (unlikely but possible) or you had the wrong kit.

Cloaked
06-05-2013, 05:29 PM
O-ring experience(s)......

Be careful on how you place the fuel tube back in the seated area. The inclination is to put the o-ring on the fuel tube and push it into it's respective seating area. The o-ring can disconfigure if you are not very careful and gentle with placing the tube in the seat. Put it in easy, use a little lube (soap suds?) and make sure you visually confirm the o-ring did not get discombobulated when installing (both ends). There is one of several opportunities to rush with reassembly and have a leak...

Been there more than once.....

.

Cloaked
06-05-2013, 05:29 PM
That brass piece comes out! It has an o-ring on both ends. However, my kit did not include the o-rings for it so be careful or replace them with o-rings you can find locally.

Mine runs great after the rebuild!The kit should have a variety of o-rings to fit your application.

.

thatsmrmastercraft
06-05-2013, 05:31 PM
O-ring experience(s)......

Be careful on how you place the fuel tube back in the seated area. The inclination is to put the o-ring on the fuel tube and push it into it's respective seating area. The o-ring can disconfigure if you are not very careful and gentle with placing the tube in the seat. Put it in easy, use a little lube (soap suds?) and make sure you visually confirm the o-ring did not get discombobulated when installing (both ends). There is one of several opportunities to rush with reassembly and have a leak...

Been there more than once.....

.

Oh sure, get all technical on us. :rolleyes: :D :D




Really good point. :toast:

catamount
06-05-2013, 05:52 PM
I had a similar o-ring issue with my fuel transfer tube. The end at the secondary was not seated well and was spraying fuel all about.

Cloaked, what would be the symptom of a leak in the tube referenced above?

Replacing old o-rings is very important. If you didn't get them in your rebuild kit, either they missed putting them in (unlikely but possible) or you had the wrong kit.

Now that you mention it, I may very have had those o-rings in the kit but thought they were too small to be used on that brass tube. Oh well, I still have those o-rings so this is an easy fix.

Cloaked
06-05-2013, 06:10 PM
I had a similar o-ring issue with my fuel transfer tube. The end at the secondary was not seated well and was spraying fuel all about.

Cloaked, what would be the symptom of a leak in the tube referenced above?



Now that you mention it, I may very have had those o-rings in the kit but thought they were too small to be used on that brass tube. Oh well, I still have those o-rings so this is an easy fix.Symptom is fuel leaking out of one end or the other... The cause can be one of two things; 1) o-rings not properly in place or 2) the tube is not seated properly (regardless of the o-ring, assuming it is installed properly). There is a far fetched possibility of a tube that has a pinhole leak somewhere.

You can fine o-rings at the hardware store... They are common items per se....

I have also seen the bowl screws (front and rear) leak because of the same issue, not seating the washers properly and there is where fuel can leak also (obviously)....the washers of olden days used to be cork and would tear easily upon reassembly.... Clean the recessed area under the screw head where the washer seats...I have seen leftover residue that will not allow a new washer to seat well.

Thanks for the great documentary of your rebuild. This goes in my PowerPoint collection...

One more word from experience... patience :D

.

pbgbottle
06-05-2013, 09:50 PM
Thanks for the info. I hope the orings are there. I ordered the same kit. That was the right kit for your carb And mine
We had the same model number.

pbgbottle
06-20-2013, 11:53 PM
quick question for u catamount did u change your pump cam ?

yours is sorta red mine is white. and this info i found said it should be pink see pics with 2.5 power valve. .
just curious because i rebuilt my carb and off idle on tip in . it dumps a ton of fuel in there almost floods chokes my engine. otherwise she runs fine. i just picked up some cams and a 2.5 power valve gonna try and replicate the oem specs from back in the day .
any info would be grealty appreciated. i think the PO must of changed mine



,,,,,,,,,

catamount
06-21-2013, 01:16 AM
I didn't touch the AP cam. I figured that whatever was there was working (and it was). Also, your spec sheet lists a 2.5 power valve but Holley sent me a 5.5 in the renew kit. I assume that Holley knows what it's doing so I used the parts in the kit.

Let us know how it works out for you though.

thatsmrmastercraft
06-21-2013, 01:27 AM
I have come across a number of applications where Holley uses the 5.5 power valve in the 240 hp version and the boat has run quite well so equipped.

thatsmrmastercraft
06-21-2013, 01:29 AM
quick question for u catamount did u change your pump cam ?

yours is sorta red mine is white. and this info i found said it should be pink see pics with 2.5 power valve. .
just curious because i rebuilt my carb and off idle on tip in . it dumps a ton of fuel in there almost floods chokes my engine. otherwise she runs fine. i just picked up some cams and a 2.5 power valve gonna try and replicate the oem specs from back in the day .
any info would be grealty appreciated. i think the PO must of changed mine



,,,,,,,,,

Have you tried to go to a shorter stroke with the optional hole to back off on the amount of fuel being squirted? I assume your choke is opening fully.

pbgbottle
06-21-2013, 03:43 AM
i never noticed another hole . i will have to look ,any pics of this for reference ,

.


Have you tried to go to a shorter stroke with the optional hole to back off on the amount of fuel being squirted? I assume your choke is opening fully.

pbgbottle
06-22-2013, 01:11 AM
WOW!
i think i got it sorted out .i tried a few of the cams out .the white which i had and red like yours are very similiar in profile .I had my mechanic buddy come over and play with everythnig .we ended up with the green one in there .he thought it worked great ..ended up my real problem was my pertronix.not the carb , we took it out threw the point in and everythnig started to work itself out. it is runnig like a top now .this is my second pertronix II no more EI for me .

now for the water test . i new it had to be something simple there really isn't much to rebuilding these carbs .i have my fingers crossed .