In need of some help

[FishingFreak13]

Hi everyone, I have a 1984 150 Mercury Black Max 2 stroke motor. When I took the boat out last year It would have a lot of trouble getting started, it would just keep cranking but not turn over until it would flood than turnover. When I would get it started it would die when i put it into reverse but would eventually work. The next issue that came up was that it didn't like to idle around at all it would idle for maybe 2 or 3 mins and than shut off which is rather annoying. Finally, when I would give her to get on plane even if it was just a steady increase it would almost get up on plane and than it would shut off. The motor does run rich but that is just an adjustment thing. I was wondering if anyone has any insight or thoughts as to what could be the problem/problems. My dad and I both think it might have something to do with the carbs. Just looking for some more insight. Anything helps.

Brian

[smitty55]

It sure sounds like like carb issues but if it's running that rich you will be fouling plugs pretty fast too. Also, without knowing the service history on an engine that old there could be other issues in the ignition system like coils, powerpack, swithchbox etc that are failing. But if the carbs haven't been serviced in a long time it would be a good thing to do them anyway for a start. Good luck with it.

Cheers

[Wallyboss]

You can try running some Seafoam thru it

[Wallyboss]

ooppss

[gonefishin]

You can try running some Seafoam thru it

I couldn't agree more. I use that stuff in all seasonal equipment and it keeps them running top notch.

[scarkner]

OMG - Seafoam is amazing. My 1984 70hp Johnson was doing very similar stuff.

I drained the gas line leading to the tank and filled it with 100% Seafoam, then pumped that into the carbs and left it for about 3 hours. When I started the engine there was so much smoke that neighbours came over to see where the fire was. This grey oily crap started coming out of the exhaust (I assume that was a lot of the fouling from inside the crank case). Then lo and behold the idle started smoothing out, the RPM picked up so much I had to dial back the idle speed... way back.

Tonight I started it up and it just did... started and instantly was idling fine.

I am blown away, this was my first time using Seafoam and I tell you there is always going to be a can of it in my toolbox now!

[Kerrazy]

It sounds like it may not be holding fuel pressure, which sounds like a tired fuel pump diaphragm Should be an easy and very inexpensive repair, also check your fuel filter to.
Kerrazy

[Wallyboss]

That's why they call it Tune Up in a can!

I bought my truck used. After a few months of travelling back and forth to work I thought that my gas mileage wasn't what it was supposed to be. So I had about 1/4 tank of gas left and I poured a full can of seafoam in the tank and drove it to as close as empty possible. One can of the stuff and my gas mileage got better by about 20%. So I do it every 6 months.

[scarkner]

That's why they call it Tune Up in a can!

I bought my truck used. After a few months of travelling back and forth to work I thought that my gas mileage wasn't what it was supposed to be. So I had about 1/4 tank of gas left and I poured a full can of seafoam in the tank and drove it to as close as empty possible. One can of the stuff and my gas mileage got better by about 20%. So I do it every 6 months.

I have heard good thinks about adding it to the crank case of a 4-stroke (like your truck). Instructions suggest this use. I wonder if you will see even more improvemenmtn that way?

(sorry to hijack this thread...)

[FishingFreak13]

Thanks a lot everyone for the replys every bit of info helps. I picked up 2 bottles of the seafoam and will be running it through tomorrow. Will post how it goes.

Quick Edit:Is there anything I should know about it other than to follow the instructions?

Brian

[StarTzar]

Thanks a lot everyone for the replys every bit of info helps. I picked up 2 bottles of the seafoam and will be running it through tomorrow. Will post how it goes.

Quick Edit:Is there anything I should know about it other than to follow the instructions?

Brian

Nothing specific other than follow the instructions.
Excellent product for cleaning out gummed up carburetor jets.

[smitty55]

Quick Edit:Is there anything I should know about it other than to follow the instructions?

With 2 cans you will have way to much for just that engine. That's fine, it has many other uses than just carbs but that is where it excels. It's great for combustion chambers, fuel systems and crankcases in cars etc. Lots of extra info on the website too. I use it in all my small engine fuel for maintenance and as a stabilizer. It also prevents phase separation. If you want extra cleaning use a higher concentration. The spray can with the nozzle is great for spraying into carbs while running and into cylinders directly as a cleaner. Like Scarkner, mechanics will use it high strength for major cleaning. In fuel tanks like Dan did they recommend changing fuel filters after using the stuff. Same when you use it in the crankcase, they recommend doing an oil and filter change after treatments. For cars that fail emissions tests one can of the stuff can do wonders for minimal costs.

Good luck with your engine. Cheers

[toned]

my buddy was having a hard time getting his 1970's johnson 9.9 2-stroke to run right, and after seeing this thread we figured we'd give seafoam a try...it idled rough and would randomly die, hard starting, etc..

he brought it over last night, I disconnected the hose to the tank, emptied the gas from the hose, and filled it with seafoam...started it in the driveway with water muffs...let it run 15-20 min...once I felt all the seafoam was out of the hose, I dumped the rest of the seafoam can into the tank and left it for the night

today we were out first thing, it took 3 pulls to start it, and he says he's never seen it run that good before....it didn't die on us once, and it sounded real good

I'm a seafoam believer now

[FishingFreak13]

Just wanted to give an update on how it went for us. We got it started without the seafoam just to get it running for the first time since we winterized it, as usual took a while we definitely flooded it once which wasn't much of a surprise. When it fired up the first time I think we scared the crap out of our neighbor because we had the lever that chokes it fully pulled up and it just roared. Once we let it run for a bit we followed the instructions 90% of the way, the hose thing they provide is a piece of crap so we just ended up opening the carbs with a straw and spraying it in and shut it off. We let it sit for the 5 mins it says but it was more like 10 mins. When we went to start it the next time it fired right up right away. We let it run for 10 minutes or so shut it off and sprayed more into the carbs and are going to let it sit over night than start it again tomorrow and see what happens. Boy did she ever smoke when we started it, we did give our neighbors a heads up though so the fire department never came.

Thanks again for all the help guys Fish hawk once again saves the day.

[FishingFreak13]

My hopes have been dashed. The seafoam worked great for 1 day but i tried starting yesterday and it was back to its usual self starting and than instantly dying. The only way it will start is with the choke lever pulled all the way up and when it starts boy does it ever rev. Starting to think it might be more than just a tuneup unfortunately.

Brian