Bought a new long block and wondering about the coupling and gimbal bearing.

[AKJohne]

It's an Edlebrock 1410, yes? No vacuum pulldown, it's purely mechanical, and there is a specific set up procedure for it.

Chris......

Weber, essentially the same, some nuances.. and yes there is a specific procedure, still has a pull-off, its just in the choke housing and gets a vac signal directly from the carb through a orfice that is sealed with a O-ring.
I am sure I set this on the bench when I went through it a year ago. But need to check it, unfortunately boat is now in Valdez and I am in Fairbanks (370 mile separation), will need to attend to when I get there, computer access and the excellent advice I receive here will be more difficult.!

 

[achris]

Choke pull-down is adjusted by opening to full throttle and adjusting (bending) the arrowed tab to achieve the spec'd clearance between choke plate and housing. (I think 3.5mm)

 

[achris]

Weber, essentially the same, some nuances..

Just curious, why have you got a 750cfm on a SBC? The 750 was only put on the big blocks, all small blocks got the 600cfm/1409 (much better for the SBC)...

Chris...
Edit: even at 5,000rpm the most that engine will suck is about 450cfm...

 

[AKJohne]

Just curious, why have you got a 750cfm on a SBC? The 750 was only put on the big blocks, all small blocks got the 600cfm/1409 (much better for the SBC)...

Chris...
Edit: even at 5,000rpm the most that engine will suck is about 450cfm...

Actually the 750 is pretty common from what I have seen, it was the factory 4 bbl in 97. If one does the math on cfm requirements for a 350 a 600 cfm would be more than adequate. However my experience indicates there is no downside with the 750, it simply acts like a 2 bbl until the secondaries open, which on this boat is about 4K. It doesn't start spraying fuel until 4100 - 4200 rpm. At least from the nozzles above the throttle plate. It may be introducing some fuel below the plate, if so it wasn't really noticeable. Now that I know it can flow fuel from these lower nozzles I will have to look again.

 

[AKJohne]

Choke pull-down is adjusted by opening to full throttle and adjusting (bending) the arrowed tab to achieve the spec'd clearance between choke plate and housing. (I think 3.5mm)

View attachment 360413

That mechanism is not on my carb, was not removed, was never there, everything regarding the choke is on the fuel inlet side.

 

[achris]

That mechanism is not on my carb, was not removed, was never there, everything regarding the choke is on the fuel inlet side.

Curious....

Next time you're close by, could you get some photos?

 

[AKJohne]

This is some pics from the carb rebuild thread, i dont know how to share the link.

Fuel burn with 5.7 LX mercruiser, 24' Boat​

 

[achris]

I dont know how to share the link.

 

[AKJohne]

Not available when in the app on the smartypants phone, some pics here, I may have more at the shop and will look tomorrowhttps://forums.iboats.com/threads/f...mercruiser-24-boat.730493/page-2#post-5661630,

 

[AKJohne]

We made a trip last week, put on 476 miles, (fuel was $5.80 in Valdez EKK...!) I reset the choke, which was too tight, starts right up and no black smoke.
Some pics of the carb and new engine.

 

[AKJohne]

Some pics of the O2 sensor location.

 

[AKJohne]

I had a fuel problem pop up on this trip, I think it was of my own doing. When we put this boat together the motor/drive has a water separator/filter mounted on the block and hard plumbed to the fuel pump and carb. the boat came with a Racor with a drainable bowl. From my research some people run dual filters and thats what I did. I had no issues with that arrangement in 580 hours. When I put in the new LB I converted to a electric fuel pump and retained the dual filters.

Last trip we put on 20+ hours with no issues, this trip we put in another 15 or 20 when I experienced a loss of power at fast cruise (4200 rpm). The motor never quit but would not accelerate. We had been running for about 20 minutes at that RPM. I happened to be looking at the chartplotter when this happened and the first thing I noticed was very high MPG reading and then zero flow on the fuel gauge. Indicating loss of fuel. We were not out and have never had fuel issues on this boat and stored with locking fuel cap.
I put a new filter on when we put the boat in the water in 2018, I had drained the bowl every now and then and would sometimes get a drop or two of water. This year I put on a new filter and when I removed the bowl there were a few aluminum chips and other particle's, very minor, tank was built new in 2018.

In any case we got moving again and 20 minutes later same thing, loss of power no flow. Made it back to port, filled the tank and headed back out to Unakwik, a 50 mile run and no issues, all at cruise speed but slightly slower, 3400-3800.

We hung out shrimped/fished for a few days w/no issues. then headed to Naked Island ~ 25 miles and it happened again, soon enough we got going, drifted, anchored, fished and headed back, 20 minutes in same thing this time we are DITW and no restart.

I had drained bowl and blew back through fuel line to tank from Racor when in the Harbor. I am now running on the kicker, the Admiral is driving. I remove the Lowrance fuel flow sensor w/no luck, I bypass the OP switch and hot wire the fuel pump. The motor finally starts and I think I have identified the problem.

We hang out overnight, start out the next morning with FP hot wired, pull pots, head out and it will not accelerate past 2K. We go about 10 miles in this manner and after about 15 miles I slowly accelerate to 3200 and was able to maintain that back to port ~ 35 miles. I am stumped, flummoxed as it were.... Its got to be a fuel problem, right? More to come.

 

[alldodge]

Two filters will help with keeping fuel clean but also can cause the pump to work harder. Many folks like the Racor see thru drainable filters but they are not allowed on a gas motor, diesel ok and Outboards.

Have you tried opening the gas cap when it dies to see if your drawing a vacuum on the tank? If you hear air suck in then that may be your issue

Have you checked the antisiphon valve on the tank? You seem to run fine with a full tank but problems when its not full.

The spring on the carb is not needed but wont hurt anything either

 

[Scott06]

Nice to see the project coming together after all this time. Nice clean install with the factory brackets .

Would be interested to hear what kind of AFR you are getting. I'm going to be installing mine this weekend. I put a phenolic 1/2" or maybe 1" spacer under my carb last summer to help with hot restarts, ended up going two step up rods sizes richer and one step richer step up spring to get rid of my off idle stumble. Just want to see where it lands

 

[AKJohne]

I decide to go through the fuel system, I remove all fuel lines one by one and blow through, capturing the fuel, I remove the filters and dump the fuel into a glass container. I remove the brass adaptor nut on the carb. I blow back through the line to the tank and vent is clear. I did not remove the top of carb or pull the mechanical gauge out of the back of the tank. I went through the carb a year and half ago and have never had fuel issues with debris or water. The vertical screen in the carb is clean. I mull over my filter situation and realize I am pulling through the Racor and pushing from the pump through the 2nd filter. I contact Carter and they say that is not recommended. I eliminate the second filter and install a new pump.... I know, I know two things at once is not the best way to diagnosis, but I am running out of time. In any case, we head out and run for two hours at high throttle settings 4200 and a few WOT runs and no issues. When time permits I will bench test the old pump pushing through the filter. In my mind a pump can always push more than it can pull, however that with water, I suspect with fuel I am experiencing some form of vapor lock?

 

[AKJohne]

Nice to see the project coming together after all this time. Nice clean install with the factory brackets .

Would be interested to hear what kind of AFR you are getting. I'm going to be installing mine this weekend. I put a phenolic 1/2" or maybe 1" spacer under my carb last summer to help with hot restarts, ended up going two step up rods sizes richer and one step richer step up spring to get rid of my off idle stumble. Just want to see where it lands

I used a Edlebrock 1" riser which seems to match Ok, although I did match the intake to the riser with a router as there was a lip at the intake an ED said that is not ideal.

It was quite interesting, at start up slightly rich, once warm it typically is right at 14.6, it sure helps to set the mixture screws as small changes make a difference. Also interesting is the fact had it very close by ear.
When running at cruise and even accelerating it would be in the low to mi 13 teens, occasionally I would see numbers in the 12s and even less often in the 14s. Even under hard acceleration it would typically be in the 13s, maybe more low 13s and 12s than at cruise. You have to realize the gauge is fluctuating constantly and only see steady numbers at a idle.
I considered changing the springs on the piston, but decided to wait and see as I think slightly rich is a OK place to be.

On the last day I did a few WOT runs and saw numbers in the 14s, I also noticed a hesitation and it felt like it peaked a 4800+ and then came down. I would expect to see numbers in the 12's at this throttle setting and will address that in the future, although I only run a WOT to verify I am propped ok. Or on the rare occasion the water are flat.

Re-jetting will likely require a new jet and rod and Merc used a three step needle and three step jet, the metering pistons are different as well.
A current two step needle in a three step jet would be experiment and maybe time wasted, I think I would change these three parts to current specs and go from there as Edlebrock has pretty good chart for tuning and one would be on hos own when mixing and matching... IMHO, I am sure it can be done, it just takes time.

On a side note, I replaced the motor due to what started out a valve failure on the other pre-vortec. I Revisited my notes on the old engine and with the same prop (currently a 15.8 X 15P) I saw 4850-4900. I am surprised the Vortec does not match or exceed those numbers, However once I rejet for WOT maybe that will change, every one said "you will like the 30 more HP", but I dont think that is the case here.

Pics below 14.6 at idle
13.1 at 4200

 

[Lou C]

I agree with eliminating the second filter, especially with an electric pump any additional restrictions can cause problems, pumps can overheat, etc. The other things to check are the connections for the pump & the oil pressure safety switch, these are areas that can also cause intermittent operation of an electric fuel pump. Added to that are the relay for the fuel pump.

 

[AKJohne]

Two filters will help with keeping fuel clean but also can cause the pump to work harder. Many folks like the Racor see thru drainable filters but they are not allowed on a gas motor, diesel ok and Outboards.

Have you tried opening the gas cap when it dies to see if your drawing a vacuum on the tank? If you hear air suck in then that may be your issue

Have you checked the antisiphon valve on the tank? You seem to run fine with a full tank but problems when its not full.

The spring on the carb is not needed but wont hurt anything either

It entered my mind, I blew through the line out of the tank and it passed air in that direction, however I guess its possible that its not continuously letting air in, something else to check.

 

[AKJohne]

I agree with eliminating the second filter, especially with an electric pump any additional restrictions can cause problems, pumps can overheat, etc. The other things to check are the connections for the pump & the oil pressure safety switch, these are areas that can also cause intermittent operation of an electric fuel pump. Added to that are the relay for the fuel pump.

I did remove both connections and tightened up the female spade terminal, they are awful to get at. I should have made that more accessible. I still had issues when the pump was hot wired. There is not a relay on the fuel pump, the minimal info I got with the "pump kit" form Michigan Motorz did not indicate a relay, I checked the AMP draw before I installed the motor and it was 1.06 amps and 1.17 when deadheading, I would not think a relay would be required?

 

[AKJohne]

We did catch a few Halibut, some yelloweye and some spot shrimp...!