1998 Johnson 115 SPL

[t1799]

Hey guys,

I was hoping someone could help me out with a problem I am having with my Johnson 115 SPL. I am basically not getting to reach full power when i am underway. The boat starts and idles fine (even putts along at slow speeds fine). However, when I apply full throttle the boat simply does not go. You can feel it try to surge but it will not pick up full speed and get on plane. The weird thing is when I apply full throttle when I am in neutral, I achieve max RPM's, but when in gear it will not reach max RPM's. A couple of times it has reached full speed VERY slowly and gradually. Can anyone think of why the delay in reaching full power when engaged?

To let you know what I have done so far:
Replaced spark plugs/wires
Replaced fuel/water separator filter
Replaced fuel lines and fuel filter
Replaced fuel priming bulb

 

[oldcatamount]

Re: 1998 Johnson 115 SPL

I have read that the regulator/rectifier can be an issue with that motor and if it goes, you would be running on 2 cylinders and that would fit your description. Can't say for sure, but, it's a starting place anyway. Keep us posted!

 

[surrender]

Re: 1998 Johnson 115 SPL

First thing is check compression , then spark. Motor can run up to pretty high RPM in neutral(not something you should do, really provides no info as to how motor is running) even on just two or three cylinders. If all four are getting good spark I'd rebuild carbs. Really not hard and this will probably solve your issue. the high speed jets are probably clogged or the float(s) are not operating right.

Dont think the rectifier would be the issue. On my 88 SPL(same motor basically) when I first got it the rectifier was blown but it just wouldnt charge the battery or run the tach, motor ran fine without a good rectifier. Put a new rectifier on and tach works and battery charges, had no affect on motor performance

 

[t1799]

Re: 1998 Johnson 115 SPL

Thanks for the info guys. Yea I checked and the compression and spark is good with all the cylinders. I also thought it could be the high speed jets in the carbs but I second guessed myself due to when the engine was in neutral the max rpm's were reached but when in gear they were not. I thought the same amount of fuel and air were being sent through the carbs when the throttle was fully forward whether the engine was in neutral or not, correct? I am fairly novice with these outboards that's why I ask. Again thanks for any info y'all can help me with.

 

[surrender]

Re: 1998 Johnson 115 SPL

Well I can see how you'd think the same amount of fuel would be use in neutral or in gear but the motor under NO load(in neutral) can reach very high rpms with very little fuel. If comp, and spark are good do your carbs, you'll be surprised how good your engine runs with clean carbs.

 

[SparkieBoat]

Re: 1998 Johnson 115 SPL

yep clean carbs and check fuel pump..also replace dry rotted fuel lines.

 

[emdsapmgr]

Re: 1998 Johnson 115 SPL

You can test to decide if it is a fuel issue or a spark issue: Take a friend boating with you. When the engine won't run correctly at full throttle, remove the cowling and put an inductive timing light on each plugwire. The flashes the gun will tell you if you have good spark, weak spark, intermittent spark or none at all on each plug wire. An easy test-run with the engine under load. If you find the ignition spark is ok on all 4 wires, then you have a fuel issue. As Surrender said, the engine will run fine in neutral on 2-3 cyls, but make no power when in gear. So running in neutral is an invalid test.

 

[boobie]

Re: 1998 Johnson 115 SPL

When you're out there testing your ignition take the air silencer cover off, have a squirt can of premix fuel with you and inject some fuel in each throat of the carbs when the prob occurs. If the mtr picks up that will tell where your fuel system prob is if you have one.

 

[t1799]

Re: 1998 Johnson 115 SPL

Thanks for all the information guys. I will keep you updated with my progress.

 

[nastyquedawg]

Re: 1998 Johnson 115 SPL

I had a similiar situation 2 different times on my 1988 88hp SPL. The first time was the screen on the fuel pump was clogged with old fuel line rubber. The second time I had an air leak in the fuel line coming from the tank. Hope this provides some insight.

 

[jrspop]

Re: 1998 Johnson 115 SPL

I have a 2000 115, it would run good for a few minutes, then start missing. Changed the power pack($300.00 part), runs like a dream.

 

[curtispoguebuell]

Re: 1998 Johnson 115 SPL

I am having the exact same condition with my 2000 OIS 115. I have rebuilt carbs. The one big difference I have is my boat runs great for about 5 minutes then it hits a wall. Will not run worth a crap above 2500 rpms in gear, however if I put it in nuetral it runs great. There is a system on there that if the engine gets hot it will engage the SMART system which will not let it reach rpms above 2500. One way to test this is to unplug the temperature sending units ( tan wires going to head on both sides) Apparently if this fixes the problem then you have a bad temp sending unit, you will have to figure out which one it is. I have also been told that if that does not fix the problem by unplugging, then you have a bad power pack. I have not had the opportunity to do this yet, but here is something that is bothering me a lot, I have had the opportunity the last time I took the boat to the water I took a timing light with me, when problem started I hooked it up and observed the light pattern, it was the same on all four cylinders. I am going to take this as the fact that I have good fire, but I am convinced that I dont have a fuel problem because I have had the carbs rebuilt by my local shop once, and then because of my mistrust in the fact that there was still a problem I rebuilt them myself. I am already $1000 in to mechanics charges for things that have not fixed my boat. I need ideas other than throw parts at it. Does anybody know how the SMART system disengages the RPMS and are there any other ideas anybody has?

 

[SparkieBoat]

Re: 1998 Johnson 115 SPL

sounds like it could be fuel related...I am thinking maybe fuel pump...Have you tried pumping the bulb and see if that helps...also you can get a DVA adapter and use a multi meter to test stator, power pack and regulator/rectifier..CDI Electronics site has great trouble shooting guides and a way to test each part in their install sheet, which you can freely download..if you change the power pack i would get a new optical eye also. check your compression?? also get a spark gap tester and check for strong spark at 7/16 gap....also remove coil pack and look for any blackened signs of arcing on the silver plate behind the coils..could be breaking down under a load...you also need to test your over heat buzzer..is your engine over heating???

 

[curtispoguebuell]

Re: 1998 Johnson 115 SPL

Engine definetly not overheating, I checked with a laser thermometer in various places. Compression good, spark gap good. I will check the silver plate and also download flowcharts from CDI and follow them..Since I posted that last, I took boat out to check for temp and to see if unplugging the temp units would help by disengaging the SLOW system. It did not. i also checked with a timing light while the problem was occuring (which occured immediatly off the trailer instead of after it was warmed up). Timing light verified that all spark plugs were firing. Then it happened......I stopped to pull the plugs after running it for about three minutes under a load duplicating the problem, thinking I could see if one was fouled or dry. All looked good????? Threw some new plugs in anyway (champion QL78YC). Went to run it and it had no fire. Had to trailer it with the trolling motor. Got home put it in the garage checked it again, and I had fire. So now I either have two problems OR whatever is causing the horrible miss above 2700 RPM is intermitting causing no fire. I will update when I have checked behind the coils for arcing traces. Untill then, I am thinking I might have a bad power pack, but I thought that when power packs go bad they completely go out. This is very frusterating and the Striper are moving into the creeks on Texoma!!

 

[SparkieBoat]

Re: 1998 Johnson 115 SPL

I am very suspect of the power pack and/or the timing base. if you can get it to do the no spark thing again after you get the DVA adapter you will want to focus your test on timer base and power pack..but be sure to test your regulator/rectifier and stator also. I have a 89 200 johnson that sometime would just lose fire on one bank..i ordered a new CDI power pack and then had no spark at all..replaced the timer base and that motor runs better than new now. I think possibly the power pack shorted out the timer base or visa versa.. I actually have fallen in love with the engine and do not want to sell the boat..it is an ugly boat (20' well craft 89) but that motor runs like a banshi..cranks quickly and will idle smooth all day long..I just may cry when I have to sell it..I cant keep them all..is it wrong to be so sentimental over a boat motor??

 

[surrender]

Re: 1998 Johnson 115 SPL

Sparkie, I feel the same about my 88 Spl. Knock on wood.

 

[SparkieBoat]

Re: 1998 Johnson 115 SPL

by the way I am assuming that you have tested the kill switch wire and ruled that out.