Mercury bogs down when accelerating

Well my 2001 60 horse merc has been being moody… When I accelerate, it wants to bog down right before getting on plane. It always eventually gets there but almost wants to die when accelerating, and has a few times. I’m stumped, well sort of… It’s a 4 stroke model, with 4 carbs. My fear is the jets are partially blocked. I’ve replaced the fuel pump, got new plugs on the way, going to replace the fuel line with the hopes that maybe it’s sucking some air… Any ideas?

Also, when I go to accelerate, If I pump the bulb, it usually gets on plane just fine… I’ve done a sea foam shock where you mix a can of sea foam into 1 gallon of gas and run it with the hopes of cleaning the jets out.

The fuel line is a common culprit. I see it’s on your list to fix. Replace your fuel filter too unless it’s new-ish.

B-man wrote:

The fuel line is a common culprit. I see it’s on your list to fix. Replace your fuel filter too unless it’s new-ish.

Yes, forgot to mention I replaced the filter too already. I’m hoping it’s the fuel line. Problem arose about a year ago and I’ve ran a significant amount of sea foam through the motor since then. A marine mechanic told me that’s the cheaper alternative to having the carbs cleaned. Unless it’s the fuel lines it’s looking like I just spent a bunch on sea foam and never solved my issue…

It is approaching being 18 years old. You probably have not touched it. Put in gas and oil and expected it to run. Do you treat your car the same way, is it 18 years old.

Are you mechanically inclined?

My guess is that it is a $300 plus bill at the local marina. With probably a 3 week wait.

Four carb kits, an ultra-sonic cleaner, a gallon of simple green “purple”, some fine brass wire, a compressor to blow out all the small path ways, and the better part of day or two to do the work.

You have spent the better part of $300 plus before you count your time. Make an appointment and take it in….

djshannon wrote:

It is approaching being 18 years old. You probably have not touched it. Put in gas and oil and expected it to run. Do you treat your car the same way, is it 18 years old.

Are you mechanically inclined?

My guess is that it is a $300 plus bill at the local marina. With probably a 3 week wait.

Four carb kits, an ultra-sonic cleaner, a gallon of simple green “purple”, some fine brass wire, a compressor to blow out all the small path ways, and the better part of day or two to do the work.

You have spent the better part of $300 plus before you count your time. Make an appointment and take it in….

I’m definately mechanically inclined… All things considering when I get home from work I’m either going to be lazy and not productive or work on things that need fixing. So I think of it as saving myself a bunch of money. I would rebuild the carbs myself but I’ve never synchronized 4 carbs and don’t know anyone who has. I’ve rebuilt 20 plus carbs and I’m only 22. I’m sure I can figure it out. It’s the 3 week waiting period that’s keeping me from bringing it in. I’d rather spend the same amount of money on fixing something self vs bringing it in due to the fact I’ll have an ultrasonic cleaner and a acquiring other Misc tools from the jobs I complete. In the end, I still have the tools and will still use them vs over paying someone to do what I’m perfectly capable of.

I’ve saved myself thousands doing my own repairs to all types of engines. If for some reason I have to take this in since I don’t know how to sync carbs and I can’t find any advice or tips then it’ll be at the end of the season. I’m not letting them take my boat during prime fishing season!!!

I never bring anything in to a shop. Always fix at home. No matter what the struggle will be.

I can never justify paying mechanics prices. So we bought our own lift.

Attachments:

1. 

   20190531_213606.jpg
   

I would also drop a PM to Iowaboy. He has worked me through some issues over the phone

I would suspect fuel lines,some years used those lines with a liner that would collapse.Pumping the primer is forcing fuel past restrictions.

To synchronize carburetors,you will need a 4 gauge”sync stick”which you plug into vacuum ports.Youtube has some videos,Yamaha 4 stroke would be similar.

milemark_714 wrote:

I would suspect fuel lines,some years used those lines with a liner that would collapse.Pumping the primer is forcing fuel past restrictions.

To synchronize carburetors,you will need a 4 gauge”sync stick”which you plug into vacuum ports.Youtube has some videos,Yamaha 4 stroke would be similar.

I’ll look into that, thanks! And bearcat, that’s awesome, I’m still rolling on the floor until I buy a house lol. I’ve done just about everything a guy could do to a pickup motor… Whether it was mine or a friend’s. Screw paying them up to 100$ an hour. That’s crazy…

OK, the first thing you need to do is quit with the Seafoam. Seafoam is a detergent that only fixes mild varnish issues in carbs. It’s like a light switch, it either works or it don’t. Armchair mechanics treat this stuff like it’s some kind of magic snake oil and if a litle doesn’t work, try 10 gallons of it. Your engine was NOT designed to run on 10% Seafoam so that shock treatment idea is just a bad idea that will screw up your engine.

Since you already replaced the fuel pump, there’s a strong chance we’re looking at an air leak here and that would be the first thing I’d check.

1. If you know anybody who has a similar Merc, borrow their hose and try it. This will verify if the leak is in the hose and then you know where to look. Otherwise you’re just wasting time.

2. Next, if at all possible, try to run the engine off of portable Merc tank. This will verify if you have a fuel pickup issue in your tank.

3. If neither of those tests show where the issue is, then pop off the cowling and pump up the fuel ball. Then listen and look for leaks. Any wet spot or hissing where there’s fuel line or a clamp could be your issue.

Try the above 3 and report back.

Grouse

TheFamousGrouse wrote:

OK, the first thing you need to do is quit with the Seafoam. Seafoam is a detergent that only fixes mild varnish issues in carbs. It’s like a light switch, it either works or it don’t. Armchair mechanics treat this stuff like it’s some kind of magic snake oil and if a litle doesn’t work, try 10 gallons of it. Your engine was NOT designed to run on 10% Seafoam so that shock treatment idea is just a bad idea that will screw up your engine.

Since you already replaced the fuel pump, there’s a strong chance we’re looking at an air leak here and that would be the first thing I’d check.

1. If you know anybody who has a similar Merc, borrow their hose and try it. This will verify if the leak is in the hose and then you know where to look. Otherwise you’re just wasting time.

2. Next, if at all possible, try to run the engine off of portable Merc tank. This will verify if you have a fuel pickup issue in your tank.

3. If neither of those tests show where the issue is, then pop off the cowling and pump up the fuel ball. Then listen and look for leaks. Any wet spot or hissing where there’s fuel line or a clamp could be your issue.

Try the above 3 and report back.

Grouse

I’ll give it a shot tonight. Seafoam is petrolium based and an is guaranteed to not harm an engine. Seafoam says you can’t harm an engine no matter how much you put through it. If the above doesn’t work, I’ll try to harm the engine with seafoam and take them up on that guarantee lol.

I’ve got a long enough section of hose, I’m going to replace the exposed section that sees the sun day in and day out first then run that into a can of gas. Try running it in there and seeing if that fixes the issue…

Update: ii replaced the 3 feet of line I thought could be the culprit and installed new plugs tonight. Next step is water testing. The brimer bulb feels to get harder now than before. Which is a good sign!

as far as syncing the carbs,as long as you dont remove the throttle shafts or disturb the throttle plates or linkage settings you dont need to sync them other than the idle mix screws.
that can be done using the tachometer as your guide,put the idle mix screws back where you found them,say a turn and a quarter out.
start the engine and let it warm up good.

one carb at a time while watching the tach, ever so slightly adjust the screw in,once you see the rpms drop,stop there and back it out again until you see the rpms rise and then drop again.
the half way point is where you want to be.

dont ham fist the adjustments,ie,no quarter or half turns,just a tiny bit goes a long ways and let the motor settle down after each adjustment before going any further.
it doesnt matter if one carb is adjusted two turns and the next one only one turn as you are adjusting the carb for its cylinder alone and each of them will be a bit different.

check the fuel pumps strength while you are at it,with the carbs full,remove the output hose from the pump and attach a longer hose you can run into a bucket.
start the engine and let it idle,the stream should be strong and free of air bubbles.
if the stream flow is weak,the pump needs kitted,if there is air bubbles present you have a leak on the suction side of the pump.

do us a favor and do not set yourself on fire while doing the test.

Update:

I replaced the primer bulb also. No improvement. I think it’s the carbs. I notice gas coming out of the carbs when I turn the throttle. Even idling at the landing I noticed gas in the water. Gas is coming out of the top side of the carb where there is a rubber boot around a rod. (Something to do with pumping fuel) And that’s leaking on all 4 carbs. I spoke with a marine dealership and the guy said 600$ tops and they’ll rebuild and clean all 4 carbs. He said that’s the highest it’ll be. If the part is just fine, he’ll leave it and only order the parts needed. (Should save 240$ in 4 carb kits, costing around the 120$ mark for only the parts I need) In the end, he guesses it’ll be around the 400$ mark.

He’s even willing to work with my schedule. I told him I fish a lot and don’t want to sit it in the shop for any weekends. He told me to drop it off on Monday, and they’ll dig into it and order the parts I need, then I can take it for the 4th and bring it back the 8th (following Monday) and they’ll get the carbs cleaned and fixed up. I’ll post the solution but I believe it’s fuel seeping out that rubber boot where there is a diaphragm that’s not holding the fuel back. It might be as simple as replacing those 4 diaphragms and not even any carb cleaning. I’ll check back in once I hear what parts they’re ordering.

Did you ever determine the issue with your motor? I have the same motor and am having a very similar problem with it. I have tried pretty much everything you have listed above. Issue remains !

One of the carbs was dirty. An issue I didn’t have the equipment to fix, shop quoted me 600 to install carb kits on all 4 carbs. Ended up selling that boat and buying my alumacraft. When it was in the shop they mentioned the rotting transom. So it was time to sell everything and upgrade!

600 to install four carb kits???????????
cheesenrice I aint charging enough!!!!!

Iowaboy1 wrote:

600 to install four carb kits???????????
cheesenrice I aint charging enough!!!!!

I almost brought my boat in to have the carbs gone through once probably 7-8 years ago and they quoted me $125 a carb plus parts. They were on my work bench torn apart that afternoon.

I hope you disclosed that rotting transom to your buyer, that is a nightmare to deal with.

KPE wrote:

I hope you disclosed that rotting transom to your buyer, that is a nightmare to deal with.

Yes, he wanted it for the motor and is aware of everything. It’s my girlfriends dad that bought it.

I have a 1982 mercury 80 hp outboard motor. Mine starts no problem but when going full throttle it will die sometimes or takes forever to get going but it never gets top speed. I’m missing a third of the speed. When motor is trimmed full down its extremely slow and sluggish and then I start trimming it up so it will pick up speed. I used to be able to get 33 to 35 mph out of it easy no problem. Full throttle it took off like a bat out of hell. Now it’s like an 80 year person trying to run. Also never had this before but when trimming the prop up the boat starts hopping now where it never did that before. Any suggestions would be great. She’s an old but been a beauty for me for 14 years. I love her and wanna keep her going. #helpme lol

Have you done anything to it Chris?

@iowaboy1