1988 BFN - PCM 454 tune up |
Post Reply | Page 123> |
Author | |
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
Posted: April-08-2013 at 9:31pm |
After restoration of the BFN I ran it a few times and this past weekend took it out skiing. I did re-check/re-set the ignition and timing prior to skiing this weekend. Using the specs in the reference section under PCM Engine Manual (1989).
Results were Engine is a little harder to start and uses more fuel. 1) Mallory Points dwell is set at 26 (Spec is 24 - 29) Points gap is set at .015 vs the spec of .020 If I open the point gap up to the requirement of .020 the dwell drops to 15. 2) Mallory distributor initial timing is set at 9 degrees. The engine manual gives 2 different requirements 5 degrees and 9 degrees? I may change the timing to 5 degrees and re set the idle/dwell. 3) Rich fuel at start up. I am seeing significantly more black fuel smoke at start up than normal. Maybe the Holley carb needs a rebuild? Looks original I need to get the tune up dialed in and hopefully improve the performance and reduce the fuel consumption. As always suggestions would be great. |
|
Thanks.......Tom
|
|
TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
Post Options
Thanks(0)
|
Shoot, Tom- I just remembered that I owe you a phone call! Sorry I didnt get back to you a few weeks ago... you caught me in the middle of my rush to get to FL for the SJRR and I totally forgot. Did you get your issues straightened out with your strut?
1. Go with the dwell- gap is just an easier means to get the correct dwell (if you dont have a dwell meter). 2. Too much initial timing can make the engine hard to start- but I dont think you'd see a huge difference in that regard between 5 and 9 degrees. Our 454 ended up way north of that and still starts nice. So long as you start nicely and dont end up with too much final at WOT (pinging), then advance it as much as practical. Going by memory, the 454 should do fine with 35 total timing. 3. Id say if you havent rebuilt it, then do so. Cant hurt! That could very well explain your hard starts as well as your rich condition. What are you running for a prop, by the way? Following the tune up, a modern prop is the best way to wake up a boat used to pull skiers (or footers)! |
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
No sweat Tim....I did get the strut lined up. The alignment process worked and I have it dialed in. How was the FL trip? Would have loved to gone....mabey next year.
I do have a dwell meter and I gaped the points until the dwell read 26. I plan to do a carb rebuild....25 years old...probably needs it. I cannot understand why it is using significantly more fuel???? I am running the original 14 X 14 Federal. I had it rebalanced this winter. |
|
Thanks.......Tom
|
|
TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
Post Options
Thanks(0)
|
Sounds like youre good to go on the dwell. If youre using more fuel and seeing signs of running rich, then a carb rebuild may help. How are you measuring fuel usage? What types of driving/skiing are you doing when looking at the fuel economy (typical or atypical use?)?
That 14x14 will get the job done for sure... but a modern prop will really wake the boat up. Its most noticeable with a good load on it. Something to consider when everything else has been squared away and your money tree replenishes itself! FL was great- great group of folks, as usual. The 80 degree weather sure is better than CT this time of year! (Ice just went out yesterday, about darn time.) We braved the gators and did a bit of footing too- always great to get a few early season runs in. |
|
SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
Post Options
Thanks(0)
|
Some carbs use foam floats, which get saturated with gas, then run rich. Could be an explanation of your degradation.
|
|
“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
Thanks,
Any suggestions where to buy a Holley Marine carb kit? I do not have a method to check total timing. I guess I would need the dampner tape? Typical boat usage for 3 skiers while exceeding fuel usage. Agree Tim about the new tech prop. Will I get more speed out of the prop? I will get the actual RPM this weekend using the dwell meter/RPM gage. |
|
Thanks.......Tom
|
|
SNobsessed
Grand Poobah Joined: October-21-2007 Location: IA Status: Offline Points: 7102 |
Post Options
Thanks(0)
|
I just measured the timing marks 0-10 degrees & extended them out with same proportion. A white paint mark is easy to read with the strobe light. No need to buy anything.
|
|
“Beer is proof that God loves us and wants us to be happy.”
Ben Franklin |
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
Thanks Chris....Yes I can figure out the advanced timing marks like you suggest. So I am at 9 degrees at idle (700RPM). What technique to use to dial this in for best performance?
|
|
Thanks.......Tom
|
|
hotboat
Gold Member Joined: March-28-2009 Location: Conn Lake Pa Status: Offline Points: 814 |
Post Options
Thanks(0)
|
Watch the advance increase as you increase engine rpms, somewhere between 2000-3000 rpm it will not raise any more, it's at this point(advance all in ) that you would like to see 35 degrees
|
|
Brian
|
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
Thanks Brian... I am not sure I got it....After I mark the damper, Run RPM up to approx 3500 - 4000 RPM and see what the timing is at that RPM?
|
|
Thanks.......Tom
|
|
TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
Post Options
Thanks(0)
|
I would recommend timing tape rather than making your own marks on the balancer. Cost is negligible. Summit timing tape for $4
Or, even better, get a timing light with a dial that allows you to compensate for the advance on the light itself. I got a used snap on a few years ago for ~$50 and its been great to have. Just line up the zero marks on the balancer and then read your timing off the light. Tom, grab the LIST number off your carb and call the Holley Tech line. They'll tell you the exact kit number you need for a rebuild. What Brian is saying about the advance is that it should be "all in" by about 3000 rpm. Again, total should be in the neighborhood of 35 degrees. |
|
BuffaloBFN
Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094 |
Post Options
Thanks(0)
|
Have you checked the mixture screws?
|
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
Will get the LIST number this weekend and order the kit. No I have not touched the mixture screws. I am not a carb guy at all. Most time I turn mixture screws and make things worse not better. However I have used the technique to screw the mixture screw all the way in and then back out 1 1/4 turn???
Dumb question....What do I watch to see if all the advance is in by 3000? the timing light on the balancer? |
|
Thanks.......Tom
|
|
TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
Post Options
Thanks(0)
|
Correct. 1-1/4 turns out is a good start on the idle mixture screws and will generally get you in the ballpark, but from there, they should be adjusted so that maximum vacuum is achieved with a load (in gear) at idle. Its not a bad idea to turn them all the way in to verify that the engine stalls. If it doesnt, then its running off the transition circuit (not the idle circuit) and something is plugged up (ie, rebuild time for sure). |
|
SN206
Grand Poobah Joined: February-25-2009 Location: Fort Worth, TX Status: Offline Points: 2339 |
Post Options
Thanks(0)
|
Tom, you did have your old prop refurbed, may have some affect? What about any uninttended adjustments when going through the tank this winter? We skiied that thing pretty hard for a 1/2 tank.
|
|
...those who have fallen and those who will.
|
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
I plan to reset the timing and adjust the carb mixture screws. (will do a carb rebuild the following week)
Then I can run it and determine the actual RPM at WOT and speed. I will have my tach/dwell meter so I can also verify the dash tach. Then I can make a decision on a new prop from delta. I need to get a few more MPH on top end. Any thoughts???? |
|
Thanks.......Tom
|
|
TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
Post Options
Thanks(0)
|
I think thats a good plan of attack. Im not sure you'll pick up much top end with a new prop (2mph is a pretty tall order) unless your current prop is underperforming or mismatched to the powertrain. The Federals are pretty lousy all around props, IMHO, but they turn out pretty respectable top ends. If youre talking about top end speed with a footer or 2 in tow, then a new prop will likely help, as I dont notice much of a speed loss with greater load with the Acmes.
All around performance with a modern prop (holeshot, midrange punch, speed holding, etc) will be much improved over the original Federal, though. Exactly how you use the boat will probably determine whether you'd want a 430 (13x13) or a 1598 (13x14). Id lean heavily towards the 430 on that boat, I think. |
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
Thanks Tim
Top end is 42 with this Federal (14 X 14). I use the boat strictly for Barefoot Skiing. We drive the boat to a calm water spot and run it for a couple of hours doing nothing but barefoot runs. Speeds ranging from 38 to wideopen for wake slalom. Yes last fall we were considering a new prop and I believe the Acme 430 is what we were focused on. I hope we can pick up a little top end speed..... |
|
Thanks.......Tom
|
|
TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
Post Options
Thanks(0)
|
Tom, something is wrong if youre only running 42mph unloaded. Stock performance on that boat should be in the 47mph range at 4200-4400 with the original 14x14. Get some verified performance numbers (WOT speed with a GPS and RPM) and we'll go from there.
|
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
I wanted to follow up on this and provide a status. Thanks to Tim, Ryan and other members for the guidance.
I ordered the Carb kit from Holley. My Carb list No. is 80262 1777. Holley Rebuild kit No. is 703-28. Cost with shipping $48.00.Ordered the Electronic Distributor from Performance Distributors…DUI P/N M12720RR. Purchased the custom fit (cut to length) Taylor 8MM wires from Summit and the Harmonic balancer timing tape. Lastly I purchased an Acme 1598 - 13X14 prop on a test basis from Delta. Steps are to rebuild the carb and assure it runs OK. Then change out the distributor/wires and reset idle timing and total timing. Run boat with old prop and document numbers. Start testing props. |
|
Thanks.......Tom
|
|
TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
Post Options
Thanks(0)
|
Tom, good plan... youre almost done!
|
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
Put the Acme 1598 (13 X 14) on last night and ran boat this morning. I have not done any work to the motor yet. My external tach confirmed the dash tach to be accurate. With driver and 1 passenger here are the numbers. WOT speed per the GPS is 48 MPH at 4400 RPM. The acceleration and torque is amazing. 1 foot wake slalom at 45 MPH with some throttle left :)
I am absolutely thrilled. Plan to get started on the carb and ignition this weekend. I did check the vacuum at idle in neutral and it was 13.5. |
|
Thanks.......Tom
|
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
Correction the vacuum is 15. Per the holley web site the power valve should be 1/2 of the vacuum. So would a 7.5 power valve sound correct?
|
|
Thanks.......Tom
|
|
cphase
Gold Member Joined: May-11-2010 Location: Newnan, GA Status: Offline Points: 795 |
Post Options
Thanks(0)
|
According to Holley that would be correct. |
|
cphase
Gold Member Joined: May-11-2010 Location: Newnan, GA Status: Offline Points: 795 |
Post Options
Thanks(0)
|
Tom, did you check your vaccuum in idle/nuetral or idle/forward? Just curious?
|
|
TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
Post Options
Thanks(0)
|
Tom, nothing wrong with those numbers! 4400 is perfectly acceptable and 48mph is very strong for that boat. If you wanted a bit more holeshot and pulling power, the 430 would probably put you in the 4700rpm range or so at WOT (unloaded). Night and day difference coming from the old Federal, eh? Like was mentioned, make sure you adjust the idle screws until you achieve max vacuum. I would guess that a 6.5pv would be stock and is fine. The larger the PV number, the easier it is to pull it in. A 7.5 would be fine as well. |
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
Tim I thought I would pick up 2 maybe 3 MPH with a new prop. I never dreamed it would wake this boat up like it did. It truly is like driving a different boat. Amazing……
I started rebuild of Holley last night. I bought the Berryman Chem-Dip to clean the parts. I disassembled the carb and inspected everything and here is what I found. Before remove the carb from boat I checked the choke. It was completely closed when cold. No 1/16 gap at the butterfly. When engine is warm the choke opens completely as normal. Holley sent me an 8.5 Power Valve. Should I buy a 6.5 / 7.5? Vacume with engine warmed up in neautral at idle is 15. Both floats are the black side hung Nitrophyl style. When holding the fuel bowl level both floats sit on the bottom floor of the bowl. I guess My plan is to order the floats and correct Power Valve from Holley in the morning. I need to read all the Holley instructions that came with the kit:( These are some concerns that I noticed! |
|
Thanks.......Tom
|
|
TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
Post Options
Thanks(0)
|
Tom, run the 8.5... It'll just open earlier/easier- performance will be good with it.
Only reason to consider a lower pv would be for economy. Turn the bowls upside down and make sure the floats hang level. Don't let the carb parts sit in the dip for more than a few hours (overnight is too long) as it may strip the finish off the carb! The way your boat was performing before was not quite right... Glad it was the case of a tired prop and not another issue! Hang that 14x14 on the wall, it's hardly suitable as a spare! |
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
OK Thx....I turned the bowl upside down and the float hangs in the middle of the bowl. Hard to tell if it is level due to the configuration but looks fine. Initially I thought I would replace the floats but they look fine. So is there any reason to replace them with brass ones or as good practice? Otherwise I will proceed with cleaning, blowing the parts out with shop air and reassembly...
|
|
Thanks.......Tom
|
|
tbeard
Senior Member Joined: April-26-2012 Location: Fort Worth TX Status: Offline Points: 379 |
Post Options
Thanks(0)
|
Hope I can get this back together and it works... |
|
Thanks.......Tom
|
|
Post Reply | Page 123> |
Tweet
|
Forum Jump | Forum Permissions You cannot post new topics in this forum You cannot reply to topics in this forum You cannot delete your posts in this forum You cannot edit your posts in this forum You cannot create polls in this forum You cannot vote in polls in this forum |