1999 Johnson 115 - 2200 RPM@WOT?? Please Help Me Diagnose Problem

[InshoreNut]

Abput three weeks ago I purchased a 1999 Action Craft 1720 with a 1999 Johnson 115 (Model # J115PLEE) . I have since been doing some work on her, like installing electronics, bow mount trolling motor, some additional lighting, plumbing the large livewell that was never plumbed at the factory...basically just doing the things to make her truly my own and set up for my style of fishing.

When I wet tested the boat 3 weeks ago, the engine was running fine no problems at all. But last night when I went to take her out fishing for the first time since I got her, in the hopes of putting a hurting on some snook. Dropped her in the water, lit up the engine and she would idle for a few seconds and conk out....had to give it some throtle in neutral to get it to light up but once backed off it would conk out again. Well, I figured ok she's just cold, when she warms up it will be fine. Finally got it to light up and stay lit, but idle running a little rough, still figure it cold, it will work itself out. Put it in gear and start to head away from the ramp. As soon as we cleared into the channel I drop the tabs and give it full throttle to jump up onto plane and Instead of jumping up and moving, she slowly winds up and won't go any higher than 2200 RPM at WOT while in gear, but if in neutral, she'll rev up to 5500 no problem.

We turn around and go back to the dock and proceed to try to eliminate possible causes of the problem....priming ball is staying hard; pull and empty the water separator, no change; pulled the cowel checked all the leads and boots to the plugs to make sure they were tightly seated; pulled the air intake housing to get to the choke; checked the linkages and carb throats to make sure they were opening.; check the choke, can hear the solenoid clicking and run through the adjustable range of the choke valve, No change; at this point I am thinking maybe the fuel pump crapped out, although it was recently replaced (within the last 6 or 8 months) or that perhaps there was some obstruction in the fuel line, but in the course of trying to get her lit up again, the engine flooded, so she was getting plenty of fuel, and I don't think that two weeks without being started is enough time for the carbs or fuel pump to develop enough varnish to cause a problem like this.

I've all but eliminated that this is an electrical problem.....battery is an AGM less than a year old and is putting out 12+ volts, and after i wet tested her I pulled the plugs, inspected them - they were in good shape not fouled at all, tested the compression 125 on all 4 cyls, and checked to make sure that they were generating spark . The engine ran smooth as silk durring wet test. It had not been run since then.

At this point, short of starting to disassemble things to get to the fuel pump and pull the out flow hose to see how well its pumping, I've run out of ideas. No alarms sounded at all durring my attempts to get her going except the warning beep at startup when she runs through the self diagnostic.

Spoke to the former owner, who was meticulous about keeping up the engine (with records to prove it) and she had only experienced a similar problem once before, last year after the huricanes when the boat had been sitting for about 3 weeks. Turned out that it had apparently been a bad thermostat (ther are aparently 2) which was replaced.

This evening I read the owners manual cover to cover and the engine does in fact have a safe mode, the S.L.O.W. (TM) system, that limits it to approx 2500 RPM in the event of an overheat, but the water pump is brand new and is pissing great, and temp guage is showing her running cool, so no way its overheating....this does point to the strong possibility of a bad thermostat, but if it caused the S.L.O.W. system to kick in you would figure that the overheat alarm and warning light would kick in. Unfortunately the manual doesn't say either way. It is just vauge enough to encourage a visit to a dealer or authorized mechanic, even when it could be something very simple to fix for someone with reasonable facility with tools, a basic working knowledge of outboards, and who thinks that the $60 to $80+ an hour for labor would be better spent on filling the fuel tank a few times. Looks like I'll be buying the shop manual for the engine ASAP.


Given the above, can anyone suggest some other possibilities of what the problem might be?Any insight would be greatly appreciated. Thanks in advance.

[ken2]

you said you checked the plugs after you wet tested the boat.
I would pull them again. Fouled plugs will give very similiar symtoms.

My buddy had a boat with a 115 suzuki, it ran great everytime.
Never so much as sputtered.
One day we launched, it started ok, hit the gas and it wouldn't go past 2300 or so. We thought it must be something that put the engine in safe mode or something. Turned out, just fouled plugs.

[Reel-Rascals]

InshoreNut - 9/5/2005 10:38 PM
but if in neutral, she'll rev up to 5500 no problem

I can't fix your specific problem ... but DO NOT wind up any OB without a load on her that high in neutral ! I don't even like getting an OB near 1500 RPMs in neutral.

[InshoreNut]

Reel-Rascals - 9/6/2005 11:35 AM

I can't fix your specific problem ... but DO NOT wind up any OB without a load on her that high in neutral !

It was a momentary wind up, literaly less than 2 seconds, just to see if the fuel flow was restricted when not under load

[Cricket Too]

You mentioned looking at the choke. That engine does not have a choke, it has a fuel primer and what you heard clicking is the primer solenoid. You also mentioned flooding, check the red lever on the top of the solenoid, it should be in the RUN position, if it's not and it is in the PRIME positon, then it will be constantly flooding your engine. Also look to make sure there isn't a crack in it and fuel is leaking out of it, they have been known to crack and leak before.

There is a specific start up procedure to use with these engines that are equipped with the Quickstart system, it is a system that advances the timing on cold start for easy starting, you shouldn't have to use the fast idle lever at all if everything is working correctly.

)First prime the bulb nice and hard

)Next turn the key on, not to start, but just on to where the self test beeps

)Then push the key in and hold it in for 8-10 seconds

)Next turn the key to start

The engine should fire over in a crank or two, if it falters at all after it starts you can just bump the key in a couple of quick times to give it a littel fuel.

[bobken]

check the powerpack

[Pelagic Act]

Could also be a bad ignition coil. If not, could be the Power Pack.