I think I lose my prime
 

I have a 1997 rebuilt 454 with weind supercharger . Very hard to start when it has not been used for a few days. Carburetor rebuilt, Plugs and electrical system checked and all OK new plugs. Fuel tank drained and cleaned. When it starts it must warm up to about 125° and will run on its own. Can start at any time with no problems after initial starting.Runs great it’s just hard starting. It’s like it doesn’t wanna get any fuel then it starts to sound like Hydro lock and before you know it is flooded. That fast it happens. This time I check my fuel pressure gauge in line . Zero pressure. Crank it three or four seconds. No fuel pressure. Repeat and watch fuel pressure go up but not fully. Repeat cranking procedure for the third time and fuel pressure is full.Stop cranking and Pumped throttle all the way four shots And back with throttle and add approximately 1/4 throttle and crank again . Crank and backfire and engine starts. Sounds like I’m losing prime then with the pumping of four times almost floods engine and that’s where the backfire is coming from and then it starts. Any ideas why it will be losing prime as evidence by the fuel pressure gauge? The next time I will try this procedure and not use four full throttle pumps and just use two So as not to flood engine and see what happens but at this point I’m looking for possibilities on why the fuel is not remaining in line.can not see or get to float bowls to check but from what I had mentioned it certainly sounds like no fuel in the beginning and then try to start it floods it but when it starts it’s smokes from excessive fuel A little. Does it sound like I’m on the right highway or am I going into a ditch?

Not uncommon for carbed SC'd engines to be cold blooded. Just because there is no fuel pressure in the line when its cold does not mean there isn't any fuel in the line.
Just give it a couple pumps of fuel initially and try to start for 1-2 secs. If it doesn't start, give it another pump and 1-2 seconds.

BTW, what carb?? Does it have a choke??

Definitely seems carb related although don’t stop just there. Check plug wires, FO, cap rotar and all grounds. Even cold blooded with a couple pumps should fire right up. Typically stall out if not with it without additional squirts of fuel and let idle at 1,500-1,800 for a couple minutes. You confirm PV’s okay if any. Is it a boost referenced 1050 Dom but again like griff mentioned “what carb?”

Be nice to borrow a carb to try!!!

If you ever had a backfire through the carb, you may have damaged the power valve.

Some of us lose our prime and mind. 😂

no choke on a blown motor. Have done all possible combinations every time I go to start this boat same result. The big thing is the numbers on the fuel pressure gauge. I believe that there is no fuel in the bowl or it would show some signs of wanting to start, even a burp. And the fact that when you start pumping it and evidently due to the smoke when she does get started shows Flooded condition. Using starter fluid definitely allows the engine to start much much quicker therefore showing no burnable fuel at start up until fuel pressure fills the bowls then goes into the engine to run.Been thinking of an electronic fuel pump that will run until the bowlI fills but that scares me. Also thinking about replacing the Holly double pumper that’s on it even though it was rebuilt it’s the original.

WHAT CARB ?????
How can there be no fuel in the bowls?? Pretty easy to check. Pull the sight plugs.
A mechanical fuel pump will loose prime over extended periods of sitting.

BTW, I had a hopped up 525sc with a Holley 1050, so been there and done that.

no sight glass.no fuel activating accel pump so there’s no doubt that there is no fuel in the bowl until primed a number of times. Why is there a leak down, don’t know and then electric fuel pump scares the hell out of me. I know she’s a cold blooded animal but she can’t be that cold

What make, model and size carb are you using?

Look for a number but for some reason cannot find it. Look on the carburetor body where it normally is and found nothing. This is quite disturbing. If I had an electric pump it would prime it self which would probably take care of most of the problem but after seeing what happens to Boat when there is a little bit of fuel in the bilge without knowing it, I really feel like I should stick with a mechanical pump. This is getting to be a real pain

After just several pumps, the accelerator pump will consume most of the fuel in the bowls.

Check right after engine runs. If they don’t squirt first pump, someone messed up that circuit and thus why hard starting.

Also, ignition timing crucial on these. If off at all, hard to start. Especially if retarded.

If its a Holley carb then its got sight plugs on the sides of the fuel bowls. https://www.summitracing.com/parts/hly-26-13
If you don't know where the sight plugs are then how did the floats in the fuel bowls get adjusted?? They need to be adjusted in the boat.

Blower motors just by their nature never want to start easy when cold.
They will crank for a while.

You should research what carb you have and do a search on basic carb parts and functions. No need to put an electric fuel pump if your have a properly working carb. Another suggestion would be to take the carb off and take in to a mechanic to do a quick once over.

You could be having simple needle and seat issues or a bad accelerator pump. If your losing fuel out of your bowls then is it just dumping all that fuel down into your blower possibly resulting in hard starts or fouling plugs. Something funky going on.

Take me a pic of carb and post.

Thanks getrdunn. Due to this problem I had the carburetor rebuilt new power valve needle and seat etc. etc. etc. Come hell or Highwater, but don’t quote me on that, I am going to find out that carb number from the guy who rebuilt the carburetor. I know that supercharged engine and they are hard starting usually do a lot better when you had some timing but in my boat in St. Petersburg Florida, I don’t believe that any mechanic down here knows Anything about supercharged engines. Two mechanics that I supposed to be good do nothing but scratch their heads. And I don’t know if I would trust them to change the timing and a blow up my damn motor. So basically I’m stuck between a rock and a hard place unless anyone knows of someone in the area That knows anything about supercharged motors. This is my first supercharger. All of my other racing motors were tunnel rims and leg racing boats. I am stuck and I hate being in this position and having to revert to starter fluid. That really is a no no. Safety is my first concern especially mine so if anyone knows of anyone around this area please let me know. Ciao

I thought FL was I/O supercharged capitol of the world ? Maybe tied with Michigan, but......

Been racing since I was 17 and messing with engine since I was 12. Yes I know where the site plugs are .The problem is Crawling all over the engine trying to see the fuel level Add 245 pounds and 5 foot six . I did not rebuild a carburetor but a mechanic down here did. No difference in starting before or after so the only thing that remains that was original is the carburetor casing itself so now I’m thinking about buying a new carburetor and a new fuel pump and if that doesn’t solve it then I have wasted a lot of money. My next thought was an EFI Holley EFI sniper. so here’s the deal. 1. Change to EFI with the supercharger.2 change carburetor and fuel pump and anti-siphon valve and hope for the best. 3. Get rid of the supercharger and just go back to the plain old boring four barrel with maybe an Edelbrock manifold and carburetor. Boring., keep starting it with starter fluid which I think is dangerous. SO WHAT DO YOU GUYS THINK.. Oh and by the way, does anyone know of anyone that works on Performance MerCruiser engines that maybe will take a look at it near Tampa/Saint Petersburg area? They all look at it for the money but don’t know what the hell they’re looking at. My brain is fried

Not sure if this could be an issue for you. I rebuilt a 260 mercruiser once, Vortec heads, cam, manifold, roller rockers, etc. In my wisdom I decided to remove the anti siphon valve from the fuel tank and use a straight fitting because I thought it would be a restriction. I rebuilt the stock Quadrajunk carb myself. It was also difficult to start and I often used starter fluid sprayed into the K&N velocity stack, and when I rebuilt the Quadrajunk I had to remove the choke because the new manifold did not have provision for the heat source. I later found out that someone was making an electric choke kit for Quadrajunks. Once the engine started it ran perfect and always restarted quickly. If I sat for over 30 minutes it became more difficult to start. I finally figured the fuel was draining back to the tank since I removed the anti-siphon valve, so I bought another one and installed it. After that it started like it used to, with a few pumps of the lever. You may already have checked your anti-siphon valve. It had one of those large cannister oil filter looking fuel filters and I just could not believe all that siphoned back to the tank, and perhaps it did not, but after reinstalling the anti-siphon valve it started fine.

Thanks for your reply, I am going to check the anti-siphon valve first. I’ve been thinking about the sniper by Harley EFI system but I am going to try the anti-siphon valve replacement first I thinkAnd see what happens. I would love to see what everybody else feels. Thanks very much for your reply again

I would try to help more but you have been working on engines since you were 12 :picard1:

Nobody is going to be able help you diagnose your issue if you can't provide basic information.
Rebuilding a carb is cleaning and replacing parts. Tuning a carb is whole different thing. The only way there isn't fuel in the fuel bowls is if it is leaking internally.

Looks like an ongoing problem that was never fixed. https://www.offshoreonly.com/forums/...ting-hard.html
Same mechanic rebuild the carb?? Why didn't he get it running correctly??

It's not uncommon for fuel to evaporate out of the bowls when it sits a few days.
Buying a shopping cart full of "new carbs" won't change this.

There are 2 ways fuel will "leave" your carb.
1) evaporation
2) leaking

Evaporation is normal. Heat accelerates evaporation. Airflow around the carbs accelerates evaporation. If you trailer your boat, driving down the road circulates air around your carbs. If you dock your boat where there is a breeze, air will circulate around your carbs.

Leaks can be external or internal. External carb leaks will drool fuel ONTO the intake. Internal carb leaks will drool fuel INTO the intake.

Once fuel has evaporated from the bowls, there is no chance the motor will start and run until the bowls are filled to the proper level. Not just enough for the squirter to work, but to the proper level else the idle circuits will be too lean to support steady idle.

You've mentioned that you aren't running chokes. There's very little performance penalty running a choke plate and electric actuator.

Now, filling the bowls can take a lot longer if your fuel has leaked back to the tank. Normally, a mechanical fuel pump will totally prevent fuel to backflow to the tank unless its check valves are leaking. But ANY small air leak between the fuel pump and the tank pickup WILL allow fuel to lose prime. Fittings at the pump inlet, the water separator inlet and outlet, the screw on canister filter seal, all of these can allow fuel to drain back to the tank if there is any leak whatsoever. Leaks BEFORE the pump go unnoticed because it is a suction line might never drip fuel.

So, check EVERY fitting and junction between the fuel pickup and the fuel pump inlet. Disassemble. Clean. Fresh Teflon tape. Securely tighten fittings. Replace hard or stiff hoses with new rubber. Double clamp with good wormgear clamps. Clean the sealing surface for the water separator canister. Oil or grease the seal on the canister and tighten it properly.

As far as the fuel pump itself, there are plenty of high volume mechanical marine fuel pumps. You should use a marine mechanical pump because the diaphragm vent is routed thru a hose to the carb to keep fuel from dribbling out into your bilge in the event of a ruptured diaphragm.
But I'm not sure I understand your aversion to an electric pump, especially since this is a common problem AND you run carbs with no chokes.
The usual way to wire a marine electric fuel pump is to run a hot lead from the coil + terminal to the fuel pump relay. The ground for the relay coil should run thru an oil pressure switch and also from a momentary switch at the dash.
To PRIME, you turn the key to "run" then press the momentary prime switch to fill the bowls. Then release the prime switch (the pump stops). Then pump the squirter a couple of times and hit the starter. Pump the throttle as needed, knowing for certain that your bowls are full. Initially, the pump won't run but as soon as engine oil pressure rises above 15 psi, the pump starts running again. Then, if oil pressure drops (engine quits or something happens where you lose oil pressure while running) the electric fuel pump stops. Or. Of course, when you turn off the ignition.

That way, the pump automatically turns on and off when you start or shut off the motor, and anytime you want to prime the carbs, just turn the ignition to "run" and press the prime button.

Something like the Carter Marine rotary vane pump should work ok alone for up to 500hp, as long as the anti-siphon and filter are free flowing. If you are "on the fence" on whether it is enough pump, you can keep the mechanical pumps to cover the question mark.

Just know that the mechanical pumps won't be able to suck fuel thru a "not running" positive displacement vane pump. The electric pump must be running in order for fuel to make it to the carb.

Also make sure your accelerator pump cams are in place and adjusted. I purchased a couple of 1150 doms that were new but were on display at a speed shop. Needless to say when initially checking the carbs out I quickly realized the primary excel pump cams were missing on both carbs. Not a biggy and seller immediately sent two replacements. Doubt your problem if your having same issues before and after rebuild unless.... I don't believe your issue is evaporation unless your floats are set dangerously low. Again if you can reach in and take a pic of both sides and the top of your carb minus flame arrestor would be helpful for others to maybe solve your problem. You can R&R a carb and let sit on the shelf for a week and still have enough fuel to start without priming. If you can't post pics ask a member to do for you. If your arm can't reach back far enough for pics then I'm not sure what to say.

I think I lose my mind
 

This is a fun game playing guess what carb.
A monkey can post picture, post a damn picture already.

Made me think of this Prosystems meme :)


https://cimg6.ibsrv.net/gimg/www.off...f93f4e225.jpeg

NO bro.The state is nothing but outboards. Big ass cruisers without boards for five even six outboards. Somebody gave you the wrong information but I always are not very plentiful

Hey Griff, thank you for your nice calming words and none agitating sentences. Replacing parts on a carburetor was done by him and he tuned it to the best that it could be tuned. Still with no improvement.If you have a question for him I can just give you his phone number so you Can bypass me and go directly to him. Now back to the boat. after the carburetor rebuild it acted exactly the same. As far as the float bowls being set, again you can ask him I’m sure he would appreciate it.I realize this is irritating for you which it shouldn’t be since you saw the need to reiterated to the Forum about working on car since I was 12, can you imagine how I feel trying to work on motors since I was 12 and you were trying to figure out which end of the pacifier to Use since I am 76 years young?Now back to the boat. I contacted Holley about their EFI system. They do have a marine system but the problem is the O2 sensor And water Don’t interact with each other very well. the carburetor is Coast Guard approved they cannot approve the remainder of the system and I don’t think I really want to be responsible should it blow up. I again will attempt to get some type of number off the carburetor Just to satisfy your curiosity. Maybe I need to clean the carburetor body that is underneath all the grime from the leaking fuel and you can tell me what that has to do with anything. I would really appreciate Your input Griff.Sounds like you know much more than I do about site plugs and Carburetor numbers.thanks for your Advice bro.I just couldn’t resist?

Huh ? I go to FMB every 2-3 years and yeh, there is more outboards every year but still bunch of performance boats. More older guys (50+) than younger know carbureted systems (this includes their ignitions and fuel systems)and there is no lack if older guys in Fl.

If your ever up in NH I’ll take a look for you.That’s the best I can do without more info / diagnostics /carb and rigging pics /etc

Will do and if I get him some pictures for you I’ll send them To you and thanks bro

You first step, and really your only step, should be to find a mechanic who knows what they are doing on carbed SC engines and can diagnose the issue and check over the entire engine.

I could walk you through a half dozen things to do and check, but its pointless because you have pretty much said that you are not going to do it. No reason for me to tell you what any decent mechanic who works on carbed SC'd engines will already know to do. Looks like you've been dealing with the issue for a year. Find someone who is competent who can diagnose and fix the issue.

I understand the frustration/ brain fry - EVERYONE seems to be an EXPERT until they show their cards for what they are...

Question - Are you will/capable of trailering the boat to Pompano Beach?
If yes, Jason is your man (or can possibly refer to a shop closer to home). He has a resume most shops dream of....
https://www.bxpmarine.com/

GWe thanks Griff for the most intelligent and spearheading thread it just excites the hell out of me. I really do appreciate you telling me what I will and I won’t do. Thank you. Since I have done pretty much everything that you have said with the exception of finding a number on the carburetor which seems to be your big thing, Guess I will have to find that number so that you can feel fulfilled. Since I only have one leg it’s pretty hard for me to become part of a motor enough to findThe number of the carburetor so this would excite you. Honestly, I will try two fulfill your request. Oh and if you wouldn’t mind, please send me the title of the mechanics book that shows you each step I should take just in case I forgot something that you read about.

As far as Pompano Beach to the person that told me that this would be the place to go, Thank you very much for the information. Ciao bro. Oh by the way Griff , There’s a great book that you should read it’s called classic racing engines by Karl Ludvigsen. It’s a great book and it will teach you what I already know

Is this guy for real? I WAS considering taking a little drive North to help this guy out until he turned into a dick. Good luck getting any more help from these guys with a problem that can probably be fixed in 30 minutes by someone competent.

Carburetors are like most guys. Just need two pumps and a shoulder roll. :)

[QUOTE=Maybe I need to clean the carburetor body that is underneath all the grime from the leaking fuel and you can tell me what that has to do with anything. I would really appreciate Your input Griff.Sounds like you know much more than I do about site plugs and Carburetor numbers.thanks for your Advice bro.I just couldn’t resist?[/QUOTE]


Leaking fuel??? Really... 76, over weight, 5'6", minus a leg and now leaking!!! 🙄

Broh

Well I guess I couldn't resist either when I saw the thread from less than a year ago regarding the very same subject. When you have people that care and take the time to help resolve your issue it's best not to down play them. Especially just VERY basic trouble shooting questions. Without the short answers the thread is pointless. BTW... I doubt Griff even had a pacifier but rest assured I guarantee he knows how old he is!!! 😂



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Why would I need a book?? I'm not the one with a broke boat that I don't know how to fix. Good luck.

BTW, Go look at your birth cert so you can see how old you really are.
Here is book you should read.
https://cimg4.ibsrv.net/gimg/www.off...c7000fe11f.png

Your only as old as the women you feel ! lol.

By the time this thread is over he`ll be 91! Poor guy

Maybe the 73 or 76 is referring to 1973 or 1976, one of the years he started having issues with this carb. :lolhit: