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1998 25HP 3 cylinder power / ignition problems?

J

JJGulley

New member
I have a 25HP 3 cylinder engine that we have owned since new. We have never had a single issue with this engine except the initial start up after sitting for the winter. Once it runs once, it's good for the season. Anyway we have got the boat back into the water up at the cottage and the engine starts right up when cold and runs great for the first 20 minutes or so. I can get to a location to fish, shut it down and then restart after a half hour or so. At this point I cannot give it more than 1/4 to 1/3 throttle or the engine falls flat on its face. Absolutely no power and sputtering. The engine never quits or stalls, but no power. I have replaced the plugs, checked the wires, and I do have spark at all three cylinders under a crank test. The plugs all look clean and dry. I changed the fuel filter, a few fuel lines, check the screens on the fuel pumps (2) and checked the coils per the service manual and all 3 have exact same readings. I'm at a loss here. The only other thing I can think of is that one or more of my coils is failing under load or the power pack is failing once it warms up.
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Anyone have any ideas or similar issues?

Johnson 25 Outboard MFG. 10/1998
Model #J25RMECA
Serial # G04414368​
 
Check your spark when the mtr fails. It should jump a 7/16" open air gap on a spark tester which you can buy at most parts houses for around $8.00. How is your compression??
 
I hope you have taken the oil injection unit off and thrown it away as far as you can.-------------------Rebuilt a 99 -25 Hp version some time ago and now rebuilding a 99-35 HP motor.---------------Great well built motor but run it at 50:1 mixing the gas oil yourself !!!---You have changed the impeller I hope !!-------Powerpack is expensive as well.------------Do a compression test as the first step.
 
I have not checked the compression as of yet and I really don't think that's the issue. Like I said the enging runs like brand new and then goes into an ignition type of failure. Every so often when it's happening it actually will correct itself and start running great again until you try to go WOTand then falls flat and will only run at 1/4 throttle. Does this engine have a failsafe mode or slowdown mode if it senses an issue? I have not changed the water pump impeller yet because I have a good full stream from the P port out the back of the engine.

And yes we do still have the oil injector in use. We bought this engine new in 98 and have never had a single issue with the injector unit to date. I have read numerous cases of people removing these oil injector units because of failure. If there is a way for me to verify that it may not be working normally, Then I will remove it. Another thing to consider is this enging get very light use. It's only used sparingly for about 8 to 10 weeks a year.
 
You'll know the oil system has failed when you don't get a low oil alarm and the oil tank is mostly filled with fuel blowing a piston or two 'cause the oil has been leaned out so much by fuel. Take that oiling system off of it and mix your fuel 50:1. That was a darn good mtr so you may want to keep it that way.
 
OK all, Here's*the latest on the engine.* Since my cottage is almost 9 hrs away I haven’t been able to get to camp until two weeks ago.* I did hire one of the local certified marine mechanics to look at it in my absence.* All he could find was a bent prop and he said the carb's were dirty and clogged.* After spending $450 on a triple carb rebuild, when I arrived in camp the motor was just as bad if not worse.*:mad:* I found a place in town I could order a new power pack from, at the cost of another $450 :(*and that took over a week to come in.* Luckily I had access to a spare boat and motor. We'll as my original thought process confirmed, the power pack was the culprit the entire time. Unfortunately I had to pay full retail to get one since I was already in camp. While I had the engine down, I did remove the oil injection in its entirety, Installed a fresh water pump, new thermostat assembly and a new prop.* The engine now runs as it did when new. I'm running the oil/fuel mix at 50:1 and it does appear to smoke a little more than it did with the injection system installed, but is running great at this time.
*
Thanks for all of your help
*
 
Just bought 3 ( 97 models ) from a lodge.-------They were deemed to be too troublesome to be renting them out any more.-----------Oil injection removed from all 3.--------Did not want to bother taking them in for service.----------Now time for me to go over them and repair as needed.---------Fantastic motors when properly run and maintained.
 
We've owned this motor since new in 98' and this is the first issue we have ever had in 13 years. The motor has been a real workhorse for us.
 
When you replaced the powerpack did you replace all the little recirc lines found behind it.------Saw them in bad shape on a 99 35 HP model that I have.
 
I checked all of the lines, they were all still tight and flexable so I didn't mess with them. I was afraid if I did, I would be stranded. Our camp is very remote and there is no place in town I would ever find new lines without having to special order the material.
 
racerone said:
When you replaced the powerpack did you replace all the little recirc lines found behind it.------Saw them in bad shape on a 99 35 HP model that I have.
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Hi I also have the 1999 35 3 cylinder model and everything you have said is happening to me. Where can you get a power pack from to fit these motors and how much are they?
 
Keone2010 said:
Hi I also have the 1999 35 3 cylinder model and everything you have said is happening to me. Where can you get a power pack from to fit these motors and how much are they?
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We ordered ours though, a local marina parts dept. I have also seen them on line. Unfortunately the cost is about $400-$500 every place I found.
 
JJGulley said:
OK all, Here's*the latest on the engine.* Since my cottage is almost 9 hrs away I haven’t been able to get to camp until two weeks ago.* I did hire one of the local certified marine mechanics to look at it in my absence.* All he could find was a bent prop and he said the carb's were dirty and clogged.* After spending $450 on a triple carb rebuild, when I arrived in camp the motor was just as bad if not worse.*:mad:* I found a place in town I could order a new power pack from, at the cost of another $450 :(*and that took over a week to come in.* Luckily I had access to a spare boat and motor. We'll as my original thought process confirmed, the power pack was the culprit the entire time. Unfortunately I had to pay full retail to get one since I was already in camp. While I had the engine down, I did remove the oil injection in its entirety, Installed a fresh water pump, new thermostat assembly and a new prop.* The engine now runs as it did when new. I'm running the oil/fuel mix at 50:1 and it does appear to smoke a little more than it did with the injection system installed, but is running great at this time.
*
Thanks for all of your help
*
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I had to change the power pack on my 25 in late fall 1 1/2 yrs ago
Same problem cropped up yesterday
$500 for one season is a bit much
 
What trouble shooting have you done.------Had a lady call me for a used powerpack about 4 years ago.-----Said that I would have to test it before I shipped it 1500 miles away.-------Got a call from someone 6 months later who bought that very motor from her.----Asked if I had a used stator.-----I coached the man over the phone on what / how to test.----He said ---" thank you " ---He had 2 good powerpacks and some wiring issues..------Never did call me for the used stator after he did the $2 fix.
 
racerone said:
What trouble shooting have you done.------Had a lady call me for a used powerpack about 4 years ago.-----Said that I would have to test it before I shipped it 1500 miles away.-------Got a call from someone 6 months later who bought that very motor from her.----Asked if I had a used stator.-----I coached the man over the phone on what / how to test.----He said ---" thank you " ---He had 2 good powerpacks and some wiring issues..------Never did call me for the used stator after he did the $2 fix.
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What’s the $2 fix I’m having the same problem, replaced the pack about 2 years ago and now nothing won’t start, no spark
 
Try disconnecting the kill circuit.----Hopefully the oil mixing tank and oil mixer have been taken off and thrown away.
 
racerone said:
Try disconnecting the kill circuit.----Hopefully the oil mixing tank and oil mixer have been taken off and thrown away.
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Yes the oil mixing unit has been gone for ages, I tried disconnecting the kill circuit still nothing, I tested my ignition coils and all of them seem to have bad ohm readings like last time I replaced them. What would be causing all of my coils to go bad. I did replace the coils and used the motor before changing out the power pack could it be that my old pack killed my new coils before putting on the new one
 
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