96' Mariner 40hp Dies under load/ Carburetor Flooding

[secretariatslew]

Serial Number: 06392118 1996 Mariner 40MLA- No website can match this serial number up with a motor on their databases!

Why I want to see a parts diagram: My motor runs for 30 seconds then dies-

Details:
I saw motor run perfectly when I bought it a month ago
The motor got a new factory powerhead in 2000 for unknown reasons
The fuel line is excessively long (six feet)
There is an extra priming sytem (a lawnmower like round bulb next to the pull cord) that is useless since the fitting on the carb bowl broke off and was sealed off. This extra primer connects the block to the carb bowl.
The motor looks immaculate, no fuel leaks.
I didn't drain the fuel left in the filter capsule after it ran when I bought it- next ran it 2 weeks later.
I tried to throttle it up when it runs- won't really rev much at all. I also tried pumping the main primer bulb while running- didn't help.

should be an easy explanation for an old hand.
thanks in advance- Brent from Lincoln, NE.

 

[secretariatslew]

Re: 96' Mercury Mariner 40hp Serial Number Help and Troubleshooting

Re: 96' Mercury Mariner 40hp Serial Number Help and Troubleshooting

Okay here is an update in case anyone cares.

I hooked it up to the hose and tried to run it today after I took 4 feet off of the fuel line. There was good pressure on the fuel line with a firm bulb. I pumped it until the little reservoir was full. First pull the engine ran for 4 seconds then died. Every pull thereafter the engine did not start, and I noticed that a little squirt of fuel was coming out of the air box (on the front of the carburetor) with each pull. I unscrewed the air box and saw that there was a small tube coming from the float chanber where the fuel was coming out with each pull and running down that plastic carburetor cover. Does this mean I have a float problem? Or is this what would always happen when you try to start and engine and it doesn't start?

 

[Fun Times]

Re: 96' Mercury Mariner 40hp Serial Number Help and Troubleshooting

Re: 96' Mercury Mariner 40hp Serial Number Help and Troubleshooting

Serial Number: 06392118 1996 Mariner 40MLA- No website can match this serial number up with a motor on their databases!

Why I want to see a parts diagram: My motor runs for 30 seconds then dies-

Brent from Lincoln, NE.

Hi Brent, The reason your having a hard time finding the parts to this engine is because in the second number you have the serial number as a # [six] (6), that 6 should be a G, Your serial number should look like this, Engine serial number 0G392118, Model number 7041217ED MARINER MARATHON 40 MLH/ALT, 2 CYLINDER, Engine Manufacture Date was back on 02/02/1996.

Here are your engine part for you.
http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=808744+94

Good luck.

 

[secretariatslew]

96' Mercury Mariner 40hp Bogging Down Under Load No Acceleration

96' Mercury Mariner 40hp Bogging Down Under Load No Acceleration

Thanks for the help on the serial number- you were correct.

Carburetor Issue:

So yes there was a carburetor problem.- I took it to a tech who told me that someone did a botch job on a carb rebuild using automotive parts. Got that figured out with a new kit.

New Trouble:

Now it idles fine, starts up good but bogs down under load. I was going to say this was a fuel pump issue- because that sounds nice, but now after looking at similarly afflicted ppl I realize that one of my 2 cylinders must be out. I guess the next thing to do is check spark and compression. The guy I bought it from- what a %*($. Assuming it is electrical (best case scenario) what would most commonly go out first? I am inept at electrical work although I do own a multimeter. Should I sack up and pay the $75/ hour to get it diagnosed professionally?

 

[secretariatslew]

Re: 96' Mercury Mariner 40hp Bogging Down Under Load No Acceleration

Re: 96' Mercury Mariner 40hp Bogging Down Under Load No Acceleration

I did a spark test and found that both plug wires were delivering strong spark, however when I ran current through the plugs, only one was sparking. So, hopefully the flooding caused by a botched carburetor rebuild fouled one of the plugs- and I'll be able to enjoy the lake again. Fingers crossed.

 

[secretariatslew]

Re: 96' Mercury Mariner 40hp Bogging Down Under Load No Acceleration

Re: 96' Mercury Mariner 40hp Bogging Down Under Load No Acceleration

So yesterday I bought 2 new plugs, gapped them to .04, ran it again with muffs- ran great. Next I ran it in a large tank and it moved so much water after throttling in gear that I couldn't keep enough in the tank. So then I took it out to the lake. I would give me a little more power, but still the same trouble- bogging down after I start to hit the power band (couldn't get above 8mph or so).
After leaving the lake I gave the guy I bought it from a call- no answer so I left a VM. I suspect he knew why I was calling and hit ignore. I had to contact him a month ago about the bill of sale and he asked me right away if I had taken it out yet. What I really want is to have a usable motor, not a fight. I am a second year law student with access to free legal services, but man that is a road I would rather not go down.

My next step as an amateur mechanic will be to buy a compression gauge and the factory manual.

 

[secretariatslew]

Re: 96' Mercury Mariner 40hp Bogging Down Under Load No Acceleration

Re: 96' Mercury Mariner 40hp Bogging Down Under Load No Acceleration

I bought a compression gauge and found that it had good even compression.

So I went back into the Marine Dealer that I had visited before, told them my symptoms, and asked for advice- He thought that I had a bad carburetor citing that it was improperly rebuilt to the point that the idle jet was bent. (My kit had a new one) So I looked up carburetors- got a quote for $95 used and about $300 new for both halves. Because I am neither rich nor patient, I decided to take another look at the carburetor. Earlier I had just sprayed carb choke cleaner into the high jet at the advice of the mechanic, and not actually taken it out. So I went out and got a fine screwdriver and actually took the small high speed oriface out. It was clogged with hair and debris to the point that I couldn't see light through it. I haven't taken it on the lake yet, but this likely was the trouble. So if your motor idles well but does not accelerate, it is not necessarily a major crisis. If anyone else stumbles upon this post becuase they are having trouble with their 40hp Mariner 2-Cycle 2-Cylinder Mercury made motor, then here is a link to the OEM Manual-

http://1manual.com/Mercury manuals/Service Manual PDFs/TwoStroke/826148r2/cover.pdf

 

[mrbios]

Re: 96' Mariner 40hp Dies under load/ Carburetor Flooding - thanks

Re: 96' Mariner 40hp Dies under load/ Carburetor Flooding - thanks

Thank you for posting all of that. I learned a lot as a friend had some similar issues with his motor. It really helps to see all the stuff you did, bought, etc and whether it addressed the core problem. Good job!