1988 BFN - PCM 454 tune up

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)!

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.

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 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 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?

Have you checked the mixture screws?

tbeard wrote: Dumb question....What do I watch to see if all the advance is in by 3000? the timing light on the balancer?

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).

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 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.....

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.

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.

tbeard wrote: 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?

According to Holley that would be correct.

tbeard wrote: Put the Acme 1598 (13 X 14) on WOT speed per the GPS is 48 MPH at 4400 RPM.

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.

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!

Hope I can get this back together and it works...