Can’t figure out my fuel delivery problem.

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alk

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Last summer my port engine ( 454 with 4brl quadrajet, mechanical fuel pump) got harder and harder to start. by August if it sat for more than a day or two, i had to dump some fuel into the carb to get it to fire up. Once running it was fine. And would start right back up the same day. I thought it was the accelerator pump, because when giving it gas, it didn’t spray anything into the carb ( like the other motor did). So I had my carb rebuilt over the winter.

Starboard motor fired right up today, port would not. Took the fuel line off at the carb, nothing coming out when cranking the motor. First thought was the fuel lines, pickup, etc. So I switched the plumbing around, and ran the sb tank right to the port motor pump. Still nothing. Ok, now I’m thinking it has to be the fuel pump. Surprisingly the previous owner left me a spare never installed fuel pump ( actually the previous, previous owner as per the receipt). Access was pretty bad, so it took me a couple of hours to install it. Crank the motor, still not a drop out the fuel line. I think with the big blocks there is a pushrod going up to the cam? Could that be worn out, bent, etc.? Or maybe it fell out when I dropped the pump, and I didnt notice? Maybe the pump that was sitting in a locker for 10 years was no good either?

Not sure where to go next, and running out of time - was planning to launch before next weekend. I could get a third fuel pump, for $225, but it seems unlikely to me that I have TWO bad pumps, so not that optimistic a third will help. I could go electric, for about same price, eliminating my fuel pump, cam, push rod, etc. I don’t love that idea, but seems like it would be quickest. But then I’ll have an electric pump on one motor, mechanical on the other; which i am not thrilled about. And not thrilled about elec pumps in general. Had to do one on my other boat, as there is no option for mechanical on the newer blocks - and hate the relay, oil pressure switch, fuse, wires, etc, involved - just more things to break. But I can have a Holley red marine in my mailbox tomorrow.
 
Why not set up an electric priming pump and keep the mechanical?

Sounds like the mechanical pump is loosing prime.
 
Looking at some more vidoes, I think it’s possible my first fuel pump wore out, and when I put the replacement in today, I didn’t have the pushrod properly positioned. Try again tomorrow I guess,
 
There's actually 2 possibilities, it could be that the pushrod slipped out of place, it is a tricky job for sure, there is a nice trick to it if you are careful when you do it....
OK so the pushrod is operated by the camshaft, it has to be in the proper position for the pushrod to operate the pump. Some people have used thick grease to hold the pushrod in place so it doesn't slide down while you struggle to get the pump mounted up. On the small block V8s there is a hole with a short bolt in it, that leads to the passageway for that pushrod. Now I'm not sure if there is also one on the big block.
If you remove that short bolt and get a longer bolt of the same thread size and pitch, you can slide the pushrod up in its proper position and thread the longer bolt in, till it just contacts the pushrod. This will hold it till you bolt up the pump. BUT THEN, do not forget to remove the long bolt and replace it with the short bolt! This is a time worn trick for V8 Chevrolets with mechanical pumps.
It doesn't work on the V6s like mine, there is no hole there, so I used some thick grease to hold it in place, and fast work to mount up the pump, a few f-bombs were thrown, but it got done.
Other possibility is your port side anti siphon valve is clogged or seized up, that can certainly interrupt fuel flow. I would check this before removing the pump. Just hook up a portable tank to your port side fuel line. If it works on that, then you know it's in the fuel delivery system not the pump. Now you did check for this by trying to run it on the starboard side, but did you also do that after changing the pump and not getting any fuel?
 
If I ever have to make a living as a mechanic, I’ll be dead.

Boat is running now, with new mechanical fuel pump, and new fuel pump pushrod. Here are all the things I did wrong, in case anyone else has to head down this path,

1. thought i had a carb problem, but it was a fuel pump problem. Hopefully the shop that rebuilt my carb did a good job!
2. First attempt to put my spare pump on, didn’t move the cooling hoses out of the way, so could not see, and did not notice the pushrod was all the way down. Bolted the pump on like this, and bent the pushrod, and cracked the pump housing.
3. Didn’t know yet that I bent the pushrod. When it wouldn’t go up to the cam with finger pressure, I pried it up with a screwdriver. Took two days to get it back out.
4. Ordered a Sierra pump, and picked up a pushrod at the local speed shop. I didn’t know there were anymore speed shops, so that was a nice find. But when I put the pump back on, finally with the rod and everything positioned correctly, forgot to reinstall the plug that comes out to pull the rod in and out. Had the take the pump back off, and screw the plug in.
5. On third install, the pump went right on, cranked the starter and was actually thrilled to have fuel spray in my face, as I didn’t hook the outlet line up yet. Someday I’ll tell you all the sorry of the time years ago I had to replace the fuel pump on my sailboat, finally got it running, sat down in the cockpit with a beer and cigar to celebrate.,,,

Put the line on, and the motor fired right up. I only wasted about $500 and two days and three nights.
 
Last edited:
alk said:
If I ever have to make a living as a mechanic, I’ll be dead.

Boat is running now, with new mechanical fuel pump, and new fuel pump pushrod. Here are all the things I did wrong, in case anyone else has to head down this path,

1. thought i had a carb problem, but it was a fuel pump problem,
2. First attempt to put my spare pump on, didn’t move the cooling hoses out of the way, so could not see, and did not notice the pushrod was all the way down. Bolted the pump on like this, and bent the pushrod, and cracked the pump housing.
3. Didn’t know yet that I bent the pushrod. When the it wouldn’t go up to the cam with finger pressure, I pried it up with a screwdriver. Took two days to get it back out.
4. Ordered a Sierra pump, and picked up a pushrod at the local speed shop. I didn’t know there were anymore speed shops, so that was a nice find. But when I put the pump back on, finally with the rod and everything positioned correctly, forgot to reinstall the plug the comes out to pull the rod in and out. Had the take the pump back off, and screw the plug in.
5. On third install, the pump went right on, cranked the starter and was actually thrilled to have fuel spray in my face, as I didn’t hook the outlet line up yet.

Put the line on, and the motor fired right up. I only wasted about $500 and two days and three nights.
Click to expand...

Sounds like a typical DIY repair... Glad you finally got it right
 
Not bad, only 2 days and three nights. Bonus on the speed shop find.

Glad you got it going ready for spring and good summary to possibly help someone else. (y)
 
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My typical repair is similar, replace things, break things, install things incorrectly, get lost blood replaced, stumble onto the real fix.....
 
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It's a pain for sure, but nice to have the knowledge for next time.
 
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You haven't lived (wrong) until you pull a Capitol HE10200 out from behind a 6-71, drive it several hundred miles to have the clutch rebuilt, install it, and have to pull it again because you did not line up the clutch plates on one side when you slid it in. Fortunately it was only a couple of bent clutch plates.
BTW it weighs about 400 pounds with the clutch pack. I built a saw horse inside the boat (Freedom my avatar) used a come-a-long to lift it and a gang of us carried it down the dock to get it into the car.
I'll take a bend up fuel pump over this one LOL.

Glad you have it all figured out and running!
 
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On a much smaller scale if you want to really have fun wait till your steering actuator leaks and you have the “fun” of getting the old one out without pulling the engine. After pulling the rear seats and exhaust on both sides I was able to get to it. BUT …. Removing the cotter pins for the mount bolts used on OMCs and Volvos was a 2 day ordeal involving cotter pin extractors and various other implementations of destruction & bad language…I don’t know if the locking tabs on Mercruisers are easier or not but hopefully so….
 
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Unfortunately too, little did I know until I spent days trying to sort out a similar issue, even after replacing the fuel pump with a new one (made by Carter, and the proper Crusader part number), that a bad batch came though and the actuator was slightly different than the originals. It wasn't moving enough to push enough fuel to prime the system. Once I figured it out, with the help of a 454 expert in the area, we located an alternative Carter pump, under the Sierra name, that just needed to be reclocked to fit, and they fired right up. I did think about replacing my push rods, how hard was that Alk?
 
SteveG said:
Unfortunately too, little did I know until I spent days trying to sort out a similar issue, even after replacing the fuel pump with a new one (made by Carter, and the proper Crusader part number), that a bad batch came though and the actuator was slightly different than the originals. It wasn't moving enough to push enough fuel to prime the system. Once I figured it out, with the help of a 454 expert in the area, we located an alternative Carter pump, under the Sierra name, that just needed to be reclocked to fit, and they fired right up. I did think about replacing my push rods, how hard was that Alk?
Click to expand...

How hard was replacing the fuel pump pushrod? Once I had the bent one out, it was was simple. the fuel pump has to come off, and then the plug at the bottom of the block has to come out, and the push rod drops right down. Or at least it should. New one slides right in, up to the cam. If you put some grease, especially red&tacky , on it - it will stay in place without the need for any hacksaw blades or other YouTubey tricks. Best to crank the motor while pushing up with your finger on the rod, to position it in the full up position ( on the cam) so you don’t have to compress the pump spring at all to get it on.

The problem I had was that since I bent mine, and then pried it back into the bore with a screwdriver - it didn’t drop down one mm on its own. The box end of a 13mm wrench was all I had that would fit in and grip - spent several hours pulling on the bent rod to finally get it out.

How long ago was the bad batch of pumps? I hope I didn’t just install one! Runs fine at idle, but I haven’t tried it under load yet.
 
Ah got it, literally that easy. Yes, use sticky grease to hold the rod up. I got the bad pumps last summer. I bought through MarinePartsSource.com. Carter 97843 pumps. When I contacted them in August, telling them of the issue we found, the owned the fact that there were many bad pumps received, and they were making the rounds telling people that bought them about it. Very frustrating, but glad I got it sorted out. I am curious, once I got to start my engines in the next couple of days, how easy they start. We chased everything trying to figure it out, and had no issues holding prime with a primer ball hooked up just before the pump, so we determined it was a pump issue, and dug in on it and figured it out. We noticed different springs, and pin styles between the two pumps, as well as a slightly different arm design. This is the full story I had posted on a Facebook Crusader group:

"Posting this as it may help some folks that have recently replaced fuel pumps on their 454s.

I had an issue after replacing fuel pumps with part number 97843, Carter fuel pump, from pleasurecraft. No fuel was being pumped to carb. If you primed the lines manually and really made sure they were full, the pump would work just good enough to run the engine, but after a day or two, the engine would not start again and required repriming. This was after confirming no vacuum/air leaks. It took multiple tries to figure out what was wrong, and finally a professional on these engines determined the pump was not doing it's thing when he tried to get it to pull fuel from a cup. It would not.

Upon inspection, the armature is slightly different, and the pump was missing the return tensioning spring under the arm. It also had it's retaining pin secured a bit different. We installed a slightly different Carter pump, reindexed it to fit my engine setup, and the engine immediately fired and ran like a top.

I contacted marinepartssource.com, where I purchased the pumps from back in March, and before I could even give the part number or my order number, after I explained my issue, she correctly guessed I was talking about pump 97843. She said they identified an issue with these pumps after receiving requests for hundreds of returns due to the differences I mentioned, and their lack of working (in most cases). In my odd situation, it does work, sort of, in my starboard engine, but we did have some starvation issues at first last night on a sea trial after putting the alternative pump in on my port engine. They are taking these back no questions asked, for a full refund (of course only for ones bought through them). They also said they have new batches of proper pumps available for shipping.

For those with fuel delivery issues, if you bought this pump, this is definitely something to verify, and make sure it's not the pump before you drive yourself crazy. Hopefully this helps someone."
 
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I replaced my old OEM Carter pump after 30 years of use because that yellow safety overflow hose was so crudded up I couldn’t tell if there was fuel in it or not. The only one I could find in a hurry was a Sierra made in S.Korea and it’s worked fine since I installed it in 2018. Of course me being me and naturally distrustful of aftermarket stuff I bought a genuine Carter that is sitting on my shelf in the garage with other spares lol:
Carb
Alternator
Starter
Various Cobra parts
If I ever sell this boat I’ll have to create an eBay store to sell all this stuff!
 
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