motor troubles

[alwayscatchineyes]

I have a 115 johnson and it starts fine, idles fine, and gets to top end fine but after about 10 to 15 seconds at top end it will drop the rpm's about a thousand, pick back up do the same again, pick back up then run for about 10 to 15 seconds just fine then do it again. It is like it is running out of fuel or sucking air but maybe electrical? Anyone have any suggestions what to do besides have those expensive people work on it? I checked for air leaks and don't seem to have any, I don't think it would be a fuel pump, filter is fine, maybe just got a bad tank of gas.

[mwal]

Next time your motor does this check your squeeze bulb on the gas line is it firm or collapsed? If its collapsed replace it. Pull you spark plugs are they gapped properly? Run some seafoam thru your tank to de gunk your carb's. If these remedies fail it time to visit the mechanic.

MWal

[scalescratcher]

I bought a used boat last year with a 97-98 (can't remember exactly) Johnson 115 Faststrike. It was doing the same thing. I drained all the gas and checked all the filters but it continued to do it. It would run at full RPM's (5000) for a length of time but then drop 1m-2m rpms. It would run at this level for a period and then kick back up to full 5000. I ended up taking it in and they found a bad sensor and power pack. I'll check the damages when I get home and post the charges and more specific info. I had the work done at R&R Marine. They had it done in 3 days for me and knock on wood the motor has been running great since.

[scalescratcher]

Maybe not the answer you're lookin for but here's my story. It's a '98 115 Johnson. The diagnosis was a bad optical sensor and power pack. Total damage was just over $400. I can tell you that when it went bad it was quick. I was down on the river for the first outing and it ran fine all day long. On the way back to the launch at day end it started to drop rpm's. I tried everything associated with the gas since I had bought the boat used and it had gas that was stored in it. I would have spent a good chunk of the season trying to figure out what turned out to be wrong and probably never got there. The $400 bucks was worth the peace of mind to have it run as it was intended.

[alwayscatchineyes]

I replaced the primer bulb, poured in some seafoam but didn't de-gunk the carbs, what is the best thing to use for the carbs? I've been thinking it in the carbs or a broken reed, I also replaced the plugs and gapped them correctly. Thanks for the help so far, I'll work on it this weekend and try a few things if I can't figure it out better bring it in even though I hate to.

[mwal]

Running seafoam will degunk the carbs and break loose carbon deposits.
Good Luck
Mwal

[Grabs]

Did you ever get this boat fixed? We have a similar problem with a 115 Johnson and we are trying to fix it. R&R marine says its the Power Pack (CDI Box). We are thinking we could save $200 by replacing it ourselves? Has anyone replaced a power pack on a 2000 115 Johnson? Is it complicated or fairly easy to do?

Anyone know where a guy can get the repair manuals for this motor in short order?

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Keep it wet!

www.fishingsavvy.com

'04 Duramax/Ally CC SB

[Surface Tension]

Grabs I usually buy my manuals on-line but if your in a hurry the public library should have them.