some test results for the gas guzzling 454

Ok guys, I thought I would start a new thread on this problem as the other one was getting kinda long. I got a break from the weather today and got some results for the tests you all recommended I do. First I did the vacuum test straight off the manifold at operating temp.....at around 700 RPM vacuum would flutter between 17 and 18, at 1000 it was 19, at 1500....23 with a slight flutter, at 2000 a steadier 23, at 2500 still 23, and at 3000 it dropped back to 22. If I punched it real quick and brought it back it dropped to about 12 then quickly returned to 23.

I put the timing index tape on and took the following readings....700 RPM-----10 deg., 1000 RPM----10 deg.,2000RPM----it advances 10 deg. for a total of 20 deg.,at 2500 RPM it advances 10 more deg. for a total of 30 deg.BTDC, at 3000 it's stays at the same 30 deg total advance and no matter how far I advance the engines the timing stays the same at 30 deg. BTDC.

Well, that's it guys I've done all you asked of me so far, I hope this helps you to help me, I have some doubts about the total advance on the timing, but I'll wait to hear what you all have to say. Thank you....Lee

Timing looks good. The manifold tests need to be done under load.

Now that was a stupid mistake, what was I thinkin ? Well, too late tonite , but first thing tomorrow morning.....thank you , Dave.....Lee

Lee, I'm going to link everyone to your original thread, if you don't mind. The information in that thread is relative to this continuing thread, me thinks!
http://www.marineengine.com/boat-fo...uel-consumption....help-!&p=362337#post362337


I'm going to also suggest that you use a very methodical and systematic "P of E" (process of elimination)..... going down a list one item, and one item ONLY at a time, while you verify the working function of each one.

Let's take carburetion and/or fuel delivery, for example:
Verify that you have no carburetor body leaks, no rich fuel/air mixture occurring, etc.
Check for excessive fuel pressure.
Perhaps borrow two known-to-be-working carburetors, and give them a try.
When satisfied, and/or have made a correction, fully test the change, make further corrections/replacements......, and then check this from your P of E list, and only then move to the next item.

Ignition timing;
The harmonic balancer decal must be correct for the balancer diameter, as I'm sure you know.
The OEM outer ring TDC mark must also be correct, and have NOT slipped over the years.
If suspect, a PSP (positive piston stop) procedure must be performed.
It will be a bit of a hassle, but it's the only way you are going to learn whether or not the TDC marks are accurate!

Then find out what your OEM ignition curve/limit should look like......, and check your existing advance to the OEM.



Remember, we are all at a disadvantage here by not having hands-ons, and/or an opportunity to see the boat for ourselves.
We do our best via the information offered by YOU!

.

Thank you Rick for the advice, I know what you mean about trying to fix things without hands on,it happens to me constantly with friends and relatives trying to pick a fix out of my head over the phone without me coming out to actually see the problem, plus there's usually something they've left out and without being there you just can't find it.
I have gone down a list of things and either eliminated them or replaced them. I measured the balancer before I went out to purchase the the timing tape(8")I put it on correctly and did the test 3 times to make sure and the results were the same each time. My fuel pump is mechanical, I have never seen a mechanical fuel pump increase in pressure as it aged, so I feel confident that increased pressure is not the problem. As far as the balancer ring slipping, I have inspected it with lights and mirrors and it seems to be fine , can't see any splits or fine crack lines anywhere around it. Also, I figure the chances of this happening on both engines is extremely rare,so unless I find something to the contrary I don't want to spend an inordinate amount of time looking in this area. Plus now with the indexing tape installed if it was slipping you would think that the 0 degree pointer and the tape would not line up after dozens of off and on cycles of the engine because of the slippage but that isn't the case it still lines up perfectly as it did when I first put it on. I am about to take the boat out now and check the vacuum and I will do at least 3 or 4 runs and record the results for all of them and I'll post them as soon as I return. I will also recheck the timing to see if it slipped while out under load. Thank all of you for your interest and suggestions in helping me solve this problem.....Lee

I went out a few hours ago and did the vacuum test but when I got back I couldn't get on the site for some weird reason, although now it seems all is well.Also I rechecked the timing tape and didn't find any slippage, so I think we can put that one to bed. Now for the vacuum:

Idle(700) 13 to 14 flutter

1000----16 to 17 flutter

1500----17 to 18 flutter

2000----14 solid

2500----10 to 9 flutter

3000----7 to 6 flutter

3500----4 to 3 flutter

WOT----2 to 1 flutter (3900)
The numbers were consistent thru all 3 runs, some of the ones that fluttered did steady out but that was the only difference. I will now wait for the wisdom of the forum to tell me what they think and it'll be on to the next step.

What type/brand vacuum gauge are you using?

Lee, your manifold pressure numbers are going to be rather meaningless with no load on the engine... other than your low rpm numbers.
Even if you were to take readings while under load at various rpm, Marine loads -vs- throttle plate position, are rather difficult to interpret.
IOW, with a throttle plate position that equates to let's say 3,600 rpm while under load, the plates are fairly well open.


As for the balancers, it's the outer ring that can slip on the inner crankshaft hub that can be the problem.
These are separated by a rubber membrane, and slipage can go undetected very easily.
When brand new, we punch the center hub and outer ring, so that in the future, we can tell if one has slipped by seeing if the punch marks are still in alignment.

Like suggested, the true means of checking this is the PPS procedure. Or, we simply install new balancers.
I suppose a good machine shop could check the indexing if they had a base model to go by.

Long shot here...... but by chance are the flywheels marked for TDC on these engines?


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Lee,

One thing on the gauge flutter, it's never going to look rock steady like it does on the video. I asked the same question when I rebuild my carbs a couple of years ago and went through the same process.

I think a dampened gauge will help. I believe my engines are tuned near perfectly or at least they feel that way. I get some needle shake as well using an Actron gauge.

There is a timing plate on the back of the flywheel. I haven't timed it mysels this way but I've seen the cover which is clearly marked.


Bob

Lee, another thought here.
When using the vacuum gauge for adjusting the carburetor, what we're doing is adjusting the low speed fuel metering circuits ONLY as to achieve the greater manifold pressure reading.
Once we are out of the low speed circuits (and into the primary or secondary main circuits), the low speed circuits no longer offer anything to the higher speed fuel metering.
There is a transition..... but a very quickly occuring transition, if all is working correctly.

IOW, don't chase your tail trying to solve High Speed circuit issues, by adjusting the low speed circuits.

.

bobct said:

.......... There is a timing plate on the back of the flywheel. I haven't timed it mysels this way but I've seen the cover which is clearly marked.

Click to expand...

Bob, if that is the case with Lee's also, he could bring the flywheel around to TDC and check this against his balancer TDC markings.

Rick....I took those vacuum readings while underway with the boat acting as the load,they are totally different than the readings taken without running the boat. and I don't know what other kind of load to put on the engine,unless somethings come up in the past 50 years that I don't know about, but I am listening ,loud and clear. As far as the balancer ring is concerned ,although I can't verify if it's punched or not I know how it's constructed and felt that once I applied the tape and aligned it with the timing pointer I had 2 fixed points on separate bodies and marking the distributor rotor, if one body, say the ring,were to slip,then the points wouldn't line up again. After taking 3 long runs at WOT I would think that if the ring were to slip then the marks would not line up as they did before I started as the timing indicator is fixed to the block and the tape is affixed to the balancer ring also the rotor is still pointing to #1 piston. The only thing I can do to really eliminate ring slippage theory is remove my heat exchanger to gain access to the flywheel indicator,that my engine does have,and line up the TDC marks and the recheck the balancer. This I will do as soon as I return to NJ. As far as the carb is concerned I haven't tried to adjust it in any way other than to make sure it's not loose and that all the screws are tight on the covers.
BOB....I know that a dampened gauge would help with the flutter but I'm not too concerned with it being it's within a inch of vacuum that were dealing with.'m much more interested in what the numbers mean. I've been away from this kind of work for a long time and my memory sure ain't what it used to be. I think I need a refresher course. LOL thank you ...Lee

Lee, let me show this in another fashion, but with a preface here;

The distributor's indexing and spark timing, is relative to the crankshaft angle.
We see the crankshaft angle via the TDC marking on the outer ring of the harmonic balancer.
TDC indicates ZERO (or Top Dead Center) only when aligned with the ZERO notch on the timing cover "tab".
(from the factory.... all of these markings are assumed to be good!)


We typically use the extended timing chain cover "tab degress" to view BASE advance....., and/or the progressive ignition advance when the decal is applied to the balancer.



This is a typical 454 balancer below.

The red arrows indicate the original crankshaft indexing keyway in the inner hub.
The keyway can't move or change relative to this hub.... it's all one metal piece.


The black arrow indicates the outer ring that includes the TDC marking.
The TDC mark on the outer ring can't move or change relative to itself ONLY!

The blue arrow shows where the rubber member is located between the inner and outer units.
The outer ring can definitely re-position itself on the inner hub if the rubber was to allow this....... thus leaving us with a TDC mark that is no longer indexed to the crankshaft keyway correctly.
(this is somewhat rare.... but with what's going on with your engines, it is certainly something to look into, IMO)


The two red dots would be the punch marks as to indicate if the two have slipped on one another.
(the OEM does not punch these)
Without having punched this at day one..... we do not have a means of telling whether or not the two have slipped.
Simply aligning the TDC with the zero tab mark, tells us little about true TDC....., and leaves us to assume that all is A-OK.
This is perhaps the more important part of what I'm trying to explain.


We need to know where the crankshaft is, in order to check/set Ignition Timing.
3*, 4*, 5* of unknown slipage is enough to hinder performance.


Any balancer that has slipped, can simply have a fresh TDC mark cut into it, once TDC is re-established (hense the PPS)
However, if we fail to punch the two...... we'll be back to square one if it should re-position itself again.


Again, I'm not suggesting that this is your problem.
What I'm suggesting, is that you may want to varify this given your excessive fuel burn.
It simply becomes one more item that can either be found and corrected....., or eliminated and checked off your list.

.

Rick....I understand you completely and when I get back to NJ I will move my heat exchanger to get a view thru the housing hole of the flywheel markings and match them up to the balancer. I think that'll get us on the same page.
I"m interpeting the slipping as a constant thing, now I believe that you're saying it may have slipped just once and locked itself into a new erroneous position. If that's what you mean then I totally understand,thickheaded as I am.

If I took a mark , say 10 degrees on the tape, and lined it up with the pointer , then marked the rotor at it's position at #1 on the distributor , I would have three positions to monitor the balancer point to see if it moved. After running for awhile I assumed the balancer would slip and therefore all 3 points would not line up again and verify to me that the balancer was slipping. But if it only slipped once before I applied the tape then all the points would be irrelevant as the balancer was wrong to begin with. I wrote this out , not only for my own clarity but for anyone following us that didn't understand . Now , I hope I'm correct....Lee

my gut says his balancers have not slipped.

The vac numbers look a bit weird. the idle values should have more vacuum, and the vacuum should fall off as the throttle plates are opened....not straight line but definately monotonic....your vacuum peaks around 1500.

Where (rpm) does the air valve open? Did you check the power piston for proper operation? Any dribble in the secondary bores?

Besides the carb...how's the rest of the engines' condition: how many hours, last compression test results, etc? If not original, any major internal work done? if so, when?

Mark...I haven't touched the carb in any way other than to make sure everything was tightened down and there were no obvious leaks. The engines have a little over 1000 hours on them and they look original as far as I can tell other than the starboard one, it has a pair of osco risers on it. I don't believe there has been any major work done to either engine,overall they look in very good condition and kept up. There were 2 previous owners , one had the boat the majority of it's life, the 2nd one had the boat slightly over a year then traded it on a 52 bertram. I took compression tests last week they ranged from 135 to 150 and held there. Plug wires were kind of raggedy and cracked, so I replaced the plugs,wires,rotor ,and distributor caps on both engines. They sound good and they idle smoothly,no weird noises or smells,the entire boat is in the same condition , looks well maintained and cared for. I had the props tuned last year after we pulled the boat and I replaced the port cutless bearing at the same time. There's a slight vibration on the port engine between 2400 and 2900 rpms that goes away above that. I believe the shaft may have a small bend in it , since that's the same side as the bad cutless. I'm thinking maybe he went aground or hit something with that prop and only repaired the prop. I'll have the shaft checked out when she's pulled this year. I don't know how much that shaft is affecting me as that engine will only turn to 3900 WOT vs the other one at 4200. That's about as good of a nutshell description as I can give you right now, I will check the flywheel timing marks when I get back into town, just to settle that slippage issue once and for all,I don't feel as though it slipped either but if there's a possibility of it happening then, like Rick , I would rather be sure and eliminate the possibility once and for all. Even if it's a long shot, I'm half Polish and half Italian, but that Irish guy "MURPHY" thinks he's my twin brother sometimes,if you know what I mean ! Thanks for the help....Lee

Lee, that is correct! I was not inferring that the balancers would be slipping on a continuous basis.
If either were to have slipped, it may have been a one time occurrence, or may have been a progression in small increments, and/or upon multiple occasions.
Hard to say.

Mark, I agree, the balancers slipping is a long shot! I brought this up only as a suggestion.
With a problem like this, I'd be leaving no stone unturned.


Has anyone mentioned spark plug readings?
With this type of fuel burn, there's got to be some tell tale signs somewhere in the mix.

Rick....Yes. I think I mentioned it in the first post. The old plugs I pulled out were black,not encrusted black like you would see from burning oil condition, but a coating of carbon on all of them, none had that tan orangish color that they should have had. So I knew it was running rich from the beginning, but no smoke out of the exhaust....Lee

Hey Lee,

I just re-read somthing like 41 posts over and over. Since you have little issues in igniting or compressing fuel, it seems to just boil down to metering it as the biggest pending question. What's worse is that I can rebuild those Edelbrocks without my glasses and know only a very little bit on Q-jets BUT: Since I am so close to you and NOT THAT I AM ANY DIAGNOSTIC GENUIS, but I would be happy to meet you one Sunday and see if a fresh set of eyes might help lend a hand.

RicardoMarine said:

Has anyone mentioned spark plug readings?
With this type of fuel burn, there's got to be some tell tale signs somewhere in the mix.

Click to expand...

Yeah, I also think that the engine is running rich, at least at idle/low speed. The vacuum #'s back this up. I'll bet the Q-jets need some help; best case is the idle jet metering, which should be done using the vacuum gauge, and normally NOT under load. Lee: adjust the idle jets for MAX vacuum at 700 rpm, keeping the throttle plates (idle screw) adjusted to keep the 700 rpm. Also, verify that the choke plates are wide open when warm. But, sorry, this step is not likely to help your high fuel burn situation at cruise, unless you find some carb issue causing leaks. The other guys here know these carbs better than I.

There is no way in Hell that low speed fuel metering is causing his excessive fuel burn.

Lee says in his original thread, that:

• his caburetors are AFBs, so Q-jet discussions are not going to help us much.
• he burned 23gals per hour at 3100 RPM. I'd ask: what WOT RPM can these engines achieve in this hull?
• checked the timing, it's at 10 deg. As we all know, this is BASE advance ONLY.
• the hull is clean. That takes care of that question!
• boat is averaging about 1/2 of the results that they got during another study. Whoah!
• at WOT it pegs the floscan out at over 32 gph/per engine. Perhaps his Flo-Scans are out of whack!

Ya got me!

Rick, he thought they were AFB's, they are Qjets, 80's vintage. just so ya know, its in the first thread. if the well plugs for the metering rods are leaking on the qjet....... well just my 2 cents, stated earlier. not that i have the experiance of you on marine but i know for a fact i epoxyed over 1000 of these in the 80's, it just became practice in the dealerships as we GM techs were not going to keep paying for a customer to come back after an carb rebuild with bad milage. now by no means am i trying to flame you here Rick, i respect the hell out of ya, but I would check that as he stated he believed they were original and q jets in the 7th or 8th post in the starting thread.

Ok guys, 1st....I really, really appreciate all the effort on your part to help me ! I think it's clear to all of us that this thing is dumping fuel in the mid and upper range and what I was trying to do was narrow the cause down to as few components as possible. I don't like the "let me buy this and try it system". I wanted to make sure that there weren't any major engine problems that were contributing to the problem. I think we've done that , with all of your help. I'll type out the check list just to make sure.

The carbs are q-jets.....The floscans pegged out...but the fuel tanks verified that they were right, so did various other trips where the floscan totals and the fuel put in the tank were virtually the same. Over a full tank of fuel(325 gals.)the scan total and actual fill were exactly 29 gals apart. The fuel gauges read zero,the scan read 325, and there was still 29 gals left in the tank. I like this and prefer to have more than I originally think I have. Next Rick asked what the WOT was on that engine....it is 3900rpms. The stbd. will achieve 4200 same as the test boat. The timing is set at 10* and the TAT is 30*. I will verify that the balancer hasn't slipped this weekend, by checking the flywheel timing against it. The hull is clean and the props were tuned.The engine was tuned ,no perceptible change in operation. It will troll all day long at 6knts and about 3 gph, only when I reach mid range does it go bonkers. I can only come up with one item left to cause this and it's the carbs. I'll see what the consensus of the forum is at this point. They both have over a 1000 hours on them and have had more 1000's of gallons of fuel thru them, they are 21 years old and in terms of wear I would think if you compared to a car it would equal a 50 year old auto carb. Please tell me if you think I'm off track here and thank you all, I will let you all know what happens from here....

Knuckle......Thanks a million for the offer to take a look at my boat, I hate to waste one of your Sundays, so I'll wait until I'm ready to pull my hair out and then I'll drop you a line to meet at Tommy's, I'll treat to breakfast and we'll go over to my place and take her out for a run, How's that sound ?
Thank's to you all ....Lee

the 170 series are not likely to have issues with their peened over secondary well plugs leaking.

Given the description with the added information, I'd be inclined to change the float, needle, and seat in one as a start, assuming nothing else is out of adjustment on the carb. The air valve adjustment and a stuck power piston can both contribute to a rich state.

As far as the mixture being off at idle, very common when a 750 CFM q-jet sits atop a 454 marine engine. The issue is that the idle mixture adjustments don't have much control due to the throttle plate positioning. The fix is to supply an alternate path for the idle air. The main nozzle dripping at idle is a good indicator of this condition.

Lee, ANYTIME !

As for all else, I have said NUMEROUS times that I have the greatest respect and admiration for the regulars on the forum here...LOADS ! One note however, Mark knows his q-jets...he's a Q-JET fanatic....I would look into his comments with better than huge interest. You may likely find the issues. I have Edelbrocks and LOVE them .. to me, they seem so much easier to understand and work with and when I am make a change and expect a certain result, good or bad, I get it on the Edelbrocks and usually NOT on the q-jets ('cept for air mixture)...Again, I can only say I know more about the former and little of the later.

Best of luck...

leokow said:

1.... I think it's clear to all of us that this thing is dumping fuel in the mid and upper range and what I was trying to do was narrow the cause down to as few components as possible. I don't like the "let me buy this and try it system". I wanted to make sure that there weren't any major engine problems that were contributing to the problem. I think we've done that , with all of your help. I'll type out the check list just to make sure.

2... The carbs are q-jets.....


3... The floscans pegged out...but the fuel tanks verified that they were right,

4.... Next Rick asked what the WOT was on that engine....it is 3900rpms. The stbd. will achieve 4200 same as the test boat. The timing is set at 10* and the TAT is 30*. I will verify that the balancer hasn't slipped this weekend, by checking the flywheel timing against it.

5... The hull is clean and the props were tuned.

6.... The engine was tuned ,no perceptible change in operation.

7..... I can only come up with one item left to cause this and it's the carbs. I


8.... they are 21 years old and in terms of wear I would think if you compared to a car it would equal a 50 year old auto carb. Please tell me if you think I'm off track here


9... Thank's to you all ....Lee

Click to expand...

1.... Lee, throwing parts at a problem will very likely and eventually fix the problem.
But you are correct in your thinking. This is why the P of E is so important.



2... OK.... that clears that up for me. In your original thread, you said that these were AFBs.
The Q-jet manufacturing or over-haul process involves the use of epoxy to close several machining ports.
These can fail, and dump fuel.


3... That verifies that!


4.... Lee, not only did I ask what the WOT was, but I asked what RPM the TA was "full-in" at. Even your Stbd engine WOT RPM is somewhat below specs.


5... Are you certain?


6.... Again, this takes me to ignition advance (not exclusively, per 'se), of which IMO, has not yet been fully verified.


7.....Likely, but not necessarily. However, let's revisit #2 above.


8.... No real science that supports any fair comparison between auto/marine.
The car/truck would need to be pulling a trailer up a never-ending hill, in order for any fair comparison to be made.


9... We have the accounting division preparing an invoice for you right now.

It may be worth thinking about removing the carbs and sending to Cliff's Performance during the winter. Giving him the vacuum reading he then can rebuild the carbs for you. The cost may be high but the benefit is your carbs will be perfect when he ships them back to you. I plan on doing this, but here there is no downtime here (winter), besides that I have no running problems now, but I know I will sometime because the carbs are 22 years and never been touched as far as I can tell.

When you folks are talking about Cliffs'....what is a typical fee for a complete rebuild on a 20 year old carbureator. I am also to understand that the "older" q-jets are more "valued" than the newer (15 years or less) ones?

Rick....the answer to your question "What RPM is TAT in totally ?"......The full 30* is in at 2500 RPM.... On Saturday, I will pull the heat exchanger and check the flywheel timing mark and I'll post what I find. As far as comparing the boat carb to a car, I only meant in the amount of fuel flow thru the carb.
I agree with your analogy of towing a trailer uphill forever as a comparison ,I'd only add "IN 1st Gear"......Lee

Below is an example only of a curve used for the 7.4L V/P engine.

The Degrees Advance (vertical scale to the left of the graph) seldom includes BASE advance, so it must be added when checking dynamically.

@ 2,500 rpm, this shows approx 15* of distributor (or EST module) advance........ add base of 8-10*, that's 23-25* @ 2,500 rpm.
@ 3,200 rpm, this shows approx 22* of distributor (or EST module) advance...... add base of 8-10*, that's 30-32* @ 3,200 rpm.

I'm thinking initially that Full-In by 2,500 rpm is too early.
I'd want to see your engine specific OEM curve in graph form.




The thing with your number of 30* @ 2,500 rpm, is that this generally does not cause excessive fuel burn. If anything, this would pose a Detonation potential.
Given the excessive fuel burn (and under the guise that poor ignition advance is the problem), I would have initially expected to see too little advance... perhaps only 22* @ 3,200 rpm, or so.

This leads me more towards the carbs, like the others are suggesting.