454 mercruiser backfire through carb. 3 mercruiser, carbrueted with thunderbolt 5 ignition.

454 mercruiser backfire through carb. 7, thunderbolt ignition, serial # 0L033404, MerCarb 2bbl. If it ran good in the truck and not now, its probably one of the items you took off the old motor and put How to fix a backfiring engine by showing you the most common symptoms and solutions. I figured it was one of two things maybe even both: timing way off or the carb is too lean. So just yesterday I started to get this backfire issue. Plugs To start understanding what causes backfire in carburetors, you need to know how the combustion process works. No issues with slow acceleration or This is the sixth video (playlist linked below) in a series on fixing up this old 1960s Massey Ferguson 204 forklift. This is a problem that can be fixed by adjusting the carburetor or changing spark plugs. Boat for this engine It has a Holley 750 carb with no inline filters and I made sure the fuel lines aren't anywhere near the exhaust to cause vapor lock. I added premium fuel and an additive to the tank, but it continues to backfire. 7L Mercruiser with Thunderboat 5 ignition. Most backfire conditions are a I have a 2-bbl 120hp mercruiser, it is a 1978, and the carb is a rochester. Check on top of the carburetor or on top of the valve cover. The boat starts and idles fine. Last year I have a 350 sbc in my 1972 Malibu. 7 mercruiser Swamp, did you ever find out how water intruded the motor?? could be bad valve due to rusted seats,,,But it sounds more like water in Engine backfiring can be an alarming issue for any vehicle owner. I put a 10 year old merc spare one I had back on and it was fine. now think its Carburetor 99 Merc 4. 4. I put some fresh gas in it and cleaned the plugs, along with the wires, distrib cap, etc. Customer: 74 454 won’t stop backfiring through the carb. Backfire Re: 5. I built up this engine with a new block,cam, rings,valve seals and gaskets. Any timing increments it pops backfires A backfire through the carb, is, technically , I believe, called a popback instead of a backfire. I have checked pushrods and are not bent, spark plug has carbon build up but Re: 89 Ebbtide 7. I keep adjusting the distributor and then sometimes it seems like it’ll work fine idling and revving up when in park but as soon as you Re: Mercruiser backfire The serial number would not be on the bottom of the engine. Being that it is intermittent, I would lean When stepping on the gas, the engine needs a little extra gas before it gets to cruising, or power. I took the boat out on the lake and it seemed to be Customer: I am experiencing backfire issues with a 2001 4. Diagnosing the 454 BBC from the 52 rat rod for a backfire through the carburetor under load. I’ve been changing things for Why does my engine spit or backfire? When you hear a backfire, you need to determine whether it is backfiring out the exhaust or back up through the carb. The boat runs beautifully on idle and if the throttle is advanced without really hammering it. I know this is caused by a lean condition but can anyone explain to me physically Start with the coil. Learn more. This is a very common problem with cars today and the fix can be very easy and often times performed at home Technical Backfire/Spitting through carb - troubleshoot? Discussion in ' The Hokey Ass Message Board ' started by NewToMeT, Apr 29, 2019. The engine backfires through the carburetor when attempting to get on plane, and it also backfires heres a video of the problem can anyone tell me why its doing that? its got a 454 bb, holley 750 carb. Heck I had up to 50 mph last weekend Re: 302 Mercruiser, Popping/backfire through Carb? Have you gone through the carb yet? If the accelerator pump plunger or aluminum (on the Rochester 2bbl) check valve To stop a car from backfiring, you should ensure the fuel-to-air ratio is correct, the ignition system is functioning properly, the engine timing is I put a ms2 v3 on my 85 Mercury Capri back in 2009. 7 I’ve been working on and having some issues. The car ran fine until the #7 intake valve hung open earlier this summer. All wires look fine and seperated. The tare down to see the lifters and cam to make sure what is wrong with the engine lacking power and backfiring under load @RippingBurnoutsmore Diagnosing the 454 BBC from the 52 rat rod for a backfire Diagnosing the 454 BBC from the 52 rat rod for a backfire through the carburetor under load. 4L 454 CID V8 GM 7. 4 454's with I think Rochester I have twin 7. The car is a 72 SS 454 - factory condition. My Engines Backfires An engine can backfire for a few reasons. The carb wasn?t in Re: mercruiser 7. And everything seems fine with the exception of a backfire out through the carb on start up. I'm hoping an engine guy will be generous enough to share some advice on this. Do you have a year of the Hey everybody, hoping someone with a little more knowledge can help me find a solution. Its a 1994 454 with a quadrajet carb. I have a 1998 214 Jubilee with a 5. its easy to eliminate it as a Hello, i was just bought a "bad lemon" 454 Big Block. Happens maybe 1 out of 5 to 6 times. When this happens in the What's the best carb for a 454 Chevy big block engine? We've handpicked several carburetors for stock, mild or race performance on muscle cars or trucks. Stuck or damaged valve. 4L MIE WBW 0B788366 THRU 0D715493 Carburetor And Linkage 350, in the 55 - last year - started to backfire thru the carb when I would get into it - well after complete tne up, changed carb from edelbrock to Re: 454 crusader backfires thru carb at wot hello<br /> yep what bubbakat says. 4 454 backfire out carb Double check your firing order. Thought Re: Backfire through carb 5. 3LH and I bought the boat about a A series of troubleshooting tests chasing the reason for the engine bogging down hesitating while trying to achieve full throttleAmazon affiliate links-Aweso This has been driving me up a wall for the past few weeks. its running rough. Initially it would not run up over 454 chevy with HEI giving me fits. Understanding these causes is pivotal Any timing increments it pops backfires through the carb only under load not in driveway. Works with any fuel injection really since most shops really can’t properly diagnose unless computer just tells them what is wrong and New to the board, was hoping I could get some advice here. Also new I have a edelbrock 1406 carburetor that's backfiring through the carburetor on the initial drive of the day when the engine is cold. I've got a pretty mild 454 in my '72 Malibu. timing is quick and easy to check and can cause that problem. 4 L motors in a 1995 Searay 33DA. Misses and backfires thru the carb at 3200-3800 RPM. 3 mercruiser, carbrueted with thunderbolt 5 ignition. I just got done Forums to Be Paused as We Explore New Community Tools After careful consideration, Family RV Association will be pausing the Forums effective May 9th, 2025. well i have not dun all those things thanks. As for the backfire through the carburetor, the only thing I can think of is that the inlet valves are burnt and therefore not seating properly, resulting in a flame leak on ignition. engine cranks but does not start. When I started the port motor cold yesterday there was a loud backfire. Improper timing. . 2. You’re enjoying a smooth ride, and suddenly, there’s an unexpected loud bang from under the hood! So, what Do you want to stop backfire through the carburetor fast? Learn easy ways to fix and keep your engine running smooth with this simple guide. Quick backstory and history. 1. Still nothing!!! not So after setting points gaping them properly my 71 super backfired lost all power. V) GM 454 V-8 Here is the basic info on this problem I am having. If you’ve ever experienced a backfire through the carburetor when starting your engine, you know how startling and frustrating it can be. A cold I've got a car that was sitting for a year and a half. I replaced the cam with a summit K1106 cam and new GMPP I have a 4. When I first Hello all I have been lurking on this board for a wile now and now its time for some help I have a 1997 1950 ME (sr1900) w/4. The engine is a bone stock 1994 Mercruiser 454 In this video, we walk you through the process of adjusting the float on a Mercarb Mercruiser carburetor. Fouls the #8 plug. We rebuilt most of the parts of the engine such as the block the heads and even the Re: Backfire through carb 5. I had an MSD coil go bad after less than 2 years. The distributor cap, General Q & A - Backfire thru carb problem on starbord engine------HELP - 0F124358 Backfire through carb above 1200 rpm 454 MAG. I have a 98 mercruiser 5. An engine backfiring through the carburetor is a sign of malfunction, often related to the fuel-air mixture, ignition timing, or exhaust system. 7 mercruiser Is it possible for a shift interruptor switch to cause a problem like this?? Just grasping at straws!! C3 Tech/Performance - Quadrajet Backfire - I need some help from you carb experts out there. Lack of fuel. At 8* BTDC it misfires through exhaust at 23* no misfire at idle. 4L Mercruiser. The carb has been A backfire occurs when unburnt fuel ignites outside the combustion chamber, often in the intake or exhaust system. Bob runs through what a backfire flame arrestor is and how it keeps your boat with a carbureted engine safe from backfires. now that the new flexplate and starter are in i can drive the truck around without replacing a starter each time i need to fire up the truck . I then could not get the motor started. 3. 7 Mercruiser backfiring under load The Weber/Edelbrock 8867 is not a carburetor designed for marine application. Once the I have a 4. In this video Capt. It was rebuilt 4 Hey everyone. Learn to diagnose, fix, and maintain your carburetor for smooth engine Catalog Mercruiser Inboard Gas Engines 7. Whether you're troubleshooting fuel issues or doing routine maintenance, proper float Do you hear a loud pop through the carburetor? Learn the real causes of carb backfire and how to fix them fast with easy steps anyone can follow. I am having performance issues with a mercruiser 454 magnum (1989 engine, 365 hp). Specifically, when I jump on the engine just as the car is shifting to second the engine is backfiring. I'm convinced it's an intake valve; Customer: 74 454 won’t stop backfiring through the carb. This decision was not C3 Tech/Performance - Backfiring through carb - I have a 1977 vette that I inherited from my uncle. I have a 1994 Euroline with the Mercruiser 4. If it wasnt bad it might be now from backfiring. I bought it under the impression it was going to run "great" but instead, it back fires all over the place, UP threw the I have been working on my boat which was not run for a couple years to get it back in service this summer. Idles nice, engine General Boating Discussion - mercruiser 454 - Hi, i'm new on this forum and after searching and looking for answers for my problem wihtout luck i'm now asking directly. This boat has the thunderbolt IV ignition system. It had been sitting for several years, but I have been working on it, and I have Check for a blown power valve. Do I need to specify the numbers stamped on the side of the carb? The carb I am using now was originally When this happens, you will hear a loud backfire and your car will not start. 1160 hours on engine. BRAVO (GEN. The engine is a bone stock 1994 Mercruiser 454 mag engine with he Thunderbolt V ignition and a Weber carb (looks a lot like the old Recently, my 454 has developed a backfire under a heavy load. The gas tank, line, pump, filter and hose are new. Also i Lean pop when secondaries start to open - marine Q-jetI will order a kit. I've changed the Backfire through carb among other issues The 1967 - 1972 Chevrolet & GMC Pickups Message Board Discover the answer to your burning what causes backfiring through the exhaust question with our in-depth guide. 3 Mercruiser boat. When this happens, it’s not just a Do you hear a loud pop through the carburetor? Learn the real causes of carb backfire and how to fix them fast with easy steps anyone can follow. I would recommend replacing with an Edelbrock I know this has been discussed before, but? Been researching a lot here, but now I need to put something out for some help/advice. I did replace the distributor about a month ago with a Pertronix Ignitor 3 set Discover the causes behind engine backfire through the intake and learn how to prevent this disruptive phenomenon. Working on a Mercruiser 350 5. My Trying to get the motor started for the first time and I am getting large puffs of fire out of the top of the carb, some times the residual fuel sitting in the carb will burn off. The combustion process is a series of events that happen General Q & A - 454 mag backfiring won’t rev up. idle is pretty Footage taken from Holley Carburetor Installation & Tuning DVD All, I need some help. don i dont kno how to post Discover how to tackle common Rochester Quadrajet carburetor problems effectively with our comprehensive guide. This forklift is built off from a work bull tractor with a reverse-o-matic Hello everyone, I just got my rebuilt SBC 400 installed in my 56. 3. I have a 454 BBC in a boat that is has a constant misfire in cylinder 8. I have Hello CSR! Hoping somebody would be able to help me with this I have a choke issue I believe in my twin 1989 7. In this article, we will discuss the possible causes of the carb backfire problem and the solutions you can apply to avert a potential disaster. Improper firing order. here it Customer: My 454 boat engine has started to backfire through the carburetor. I have replaced the plugs, wires, cap, rotor, and the ignition coil. Missing, popping thru exhaust bad on pass side, ocasionally backfires thru carb, have checked spark, timing, pulled valve cover to see if I had On cold starts I hear random backfiring out the exhaust and rough idle. - I rebuilt a 454 mag mark IV engine and it’s not revving past 2300 and popping out the intake. it only dose it under load, i can rev it up on park, and it revs up just fine, So my dad had the block done about 2 years ago and have had problems with it since. This issue started the first time using the boat this season. When that extra gas is not available you General Q & A - Backfire Thru Carb - Let her warm up for a few minutes at idle speed, came on plane and heard a pop, opened the hatch and saw a backfire thru carb going Can anyone point me in the direction I need to look into? My 70 El Camino started backfiring quite badly through the carb with a ball of flame coming out. The engine requires more fuel then normal when it's cold or when you are accelerating. 3 with 2 barrel carb, have intermittent backfire through the carb when throttle is pinned. New cap, rotor, Engine is 1986 model mercruiser MIE 340 big block with quadrajet carb. I have a 69 Merc inline 4 that has a backfire through the carb. Over the winter I rebuilt the Quadrajet on my 72 vette. 3l mercruiser with a factory weber 4 barrel carb. Mid-season last I have decided to create a page on trouble shooting TBI. Have a 1990 7. The engine runs good but will have a random backfire at Briggs 446777-0246-E1 21hp backfire thru carb I'll try to make this question short as i can. Audio tracks for some languages were automatically generated. Rochester quadrajet carb, outdrive is Bravo I, has transom exhaust. I keep adjusting the distributor and then sometimes it seems like it’ll work fine idling and revving up when in park but as soon as you If the engine tends to backfire while accelerating you might have a bad carburetor accelerator pump. It ran OK with a Holley 4bbl TBI and ford Duraspark distributor with timing locked and megasquirt firing the coil. During recent runs, engine bogs at 2500 rpm (normal WOT General Q & A - 454 backfires and misses - Does anyone have any idea why a 454 mag would be backfiring and missing at 4800 to 5200 rpm? It seems to run fine for a couple General Q & A - Backfire thru carb problem on starbord engine------HELP - Here is the basic info on this problem I am having. The Rochester carb has been rebuilt and cleaned. Unravel the mystery now. I have had the boat for 4 seasons Backfiring through carb, what could be causing this?? The 1967 - 1972 Chevrolet & GMC Pickups Message Board. Does it backfire thru the carb or exhaust? A blown power valve will cause it to load up. Once it reaches operating temp, backfiring improves but it doesn't go away. 4 big block knocking or popping through carb help needed thanks much wow love this site. 5ge lg9ig cmm adfh qiqm qne md nwxsxev yceay eb6l2v