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93 225hp diagnostic help

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shockman

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Have a problem with my "big johnson" has been stored for 2 yrs, have run a tank of gas through it and added isopropyl to it as I thought the problem was fuel, however I think it is electrical. boat starts fine as I attempt to accelerate it cuts out randomly as if it is dropping 3 cyl. does not stall, I take it back to shore, let it sit for an hour and attempt again, same thing, take it back to shore let it sit again 3rd time it will maybe miss a bit but then starts to run fine? and runs like a top???? it's like something needs to get hot and is then fine. has done this 3 times on 3 seperate days, same routine every time. Where do I start to find the problem?
 
Not sure how you know it is dropping 3 cylinders, but if it truly is, then you should look at the shift interrupter switch. It kills three cyls during the shifting operation to relieve stress on the gearcase.
It is located down low under the bottom carb on the stbd side, on the shift linkage, a black plastic switch. There is wiring incased inside wire loom that runs up the stbd side of the powerhead to the powerpack. It will be a black wire with a yellow stripe, and the black ground.

To test to see if the switch is causing you problems, simply disconnect it. It is Ok to run without this switch. If you have problems shifting out of gear, then get it fixed correctly.
 
Thanks dase! I do have a manual that does mention this switch but does not have a lot of info on it's location or how to quickly diagnose it. I will check it tomorrow when I get to the lake and post back my findings. I'm fairly sure it is dropping cyl's as it does not stall the engine but really cuts out the power and when I return it to idle I can tell if it okay or not by the tack which barely shows a drop in idle rpm however it is enough to show and seems to not be as smooth until it picks up those cyl's again. I will bring a timeing lite also and see if I can catch it not fireing. I believe that switch cuts one whole bank??
 
Yes, it cuts out the starboard bank, #1,3,5. If it is acting up, it would be sticking in the closed position. This is a long shot tho. Just a guess based on your "3 cyls dropping" statement.

Use the timing light and see which cyls are dropping, and post back.

Good luck.
 
Stator function is a bit tougher to test. You need what is called a DVA meter for measuring peak voltages as generated by the ignition system.
Search on this site for DVA. They can be purchased on Ebay for roughly 70 bucks.

Anyway, the very first thing I look for using a DVA meter, is the voltage at the orange primary wires that attach to the ignition coils. When running at idle that voltage should be about 190-210 v DVA. If that voltage is low, you can suspect the stator or the power pack.

Go to www.cdielectronics.com, check out the troubleshooting section and read up on the very good step-by-step debugging procedure for V6 loopers (non-optical ignition).

Search here....a TON of info is out here regarding this subject.
 
Okay scratch the shift switch, had problem getting it started so pulled plugs and could not get spark on top starboard cyl. finally got it started and brought timeing light for a ride with us, had it on that cyl but found one occasion when it cut out that it was not that cyl?? so cut out is sporatic and random as to which cyl,s drop?? also same old as to running it a couple of times with issues then low and behold runs like a top. got several water skies in and a trip to the gas dock without missing a beat?? has to be power pack or stator I would think?? seems like once it gets a chance to heat soak a bit it is fine?? not sure if stator could be intermitent like that??
 
Stator would not likely jump around cutting out random cylinders. Your problem is most likely the powerpack or the timer base. Make a thoroughinspection of the wiring connectors under that pack. There are two 4 pin rubber connectors from the timer base to the pack. Pull them apart and look at the pins very closely for corrosion, etc.

You will have to pull the flywheel to get to the timer base. Inspect the timing magnet ring that is around the center hub of the flywheel to make sure it is solid and not shifted (or cannot shift) from manufactured position.

And before replacing anything, I would double check that voltage with the DVA as I posted above.
 
Thanks will dig in today and see what I can find, the DVA may have to waite till I get back to town and track one down. May have to get home for a puller also for flywheel.
Marc
 
Okay this is getting to be a pain!! last weekend we pulled the powerpack open and inspected all connections which seemed pretty clean and happy, put everything back nice and neat. Boat ran fine, so thought hey maybe we got it. Now yesterday went for a ride and it started okay and ran good for a little while, then low and behold it missed a couple of times then ran fine for rest of the time. So if problem is intermitent will it show up on a voltage test or will it have to act up during test?? To have it looked at around here I would have to put a plate on trailer and tow it an hour away and if the stator or powerpack are replaced it will cost as much as me buying both those items from the USA and changeing them out myself. The one thing I have noticed through all this is that tac rpm seems to be a little out to luch at times?? I have replaced the reg/rect. a few years ago but the symptoms were the tac cutting out when I hit trim switch, never cause a running issue?
 
Disconnect the large red main plug on the engine and jump the solenoid to start the engine. Run the boat and see if the problem happens again. If it doesn't the problem is in the wiring to the helm. If it does happen again, it may be time to change the power pack. You need to plug that harness back in to shut the engine down.
 
Okay haven't been on here for a while but thought I would post that problem was power pack. Got to the end of my diagnosing abilities and thought if I take boat too dealer I would have to insure trailer and tow 60 miles and pay at least $200 for them to diagnose and repair plus cost of parts. The power pack in Can. from dealer is 35-40% more than can be bought on the net from U.S. So I thought why not replace and if thats not the problem I can keep replaceing electronic and electrical parts until fixed and have some spares and probably not spend a whole lot more in the long run!!??? Bought power pack, replaced and voila problem gone!
However now I have another problem that maybe Chris or daselbee can comment on?? Many years past I had a problem that when I hit the trim switch my tack would cut out or at least thats how I remember the problem? Took it to a dealer and they replaced the voltage regulater. Now what is happening when I hit trim switch my trim guage drops dead and intermitently comes back?? what up? bad ground somewhere or could this be tied to VR???
Marc
 
Hey Marc. I don't think the trim gauge going wonky on you is a VR problem. I had an older OMC 115 that was doing the same thing, move the trim and the gauge dropped off. My issue was the sending unit for the trim gauge. You could try removing the sending unit from the motor, then turning the key on and moving the sender arm through it's range of motion. While moving the sender arm slowly, watch the gauge and see if it tracks smoothly from high to low (or the other way around). Check the wiring to the gauge too, if I remember right, on your gauge it's a plug in, not individual wires. Try wiggling the plug first, might save you pulling off the sending unit.
 
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Thanks Bill for the reply, I'm not near the boat or the manual for that matter, but will try the parts fiche on here and see if I can figure out where the sending unit is and check when I get to the cabin on Thursday.
 
If it's the same as my OMC's, it's on the starboard side of the transom bracket. You have to tilt the motor all the way up for access, it should be held on with 2 flat head screws. You really don't have to remove it to test it, just have the motor all the way up, you'll see the spring loaded arm that goes against the mid section. Just move the arm up and down, with the key on, and watch the gauge. May need 2 people, depending on your boat. Good luck, let me know. :)
 
Hey Bill how about you go on the parts section and look up 1993 225hp VJ225PLETF and tell me what sending unit is?? I'm wondering if you are talking about the relays?? I don't see anything called a sending unit
 
Number 88 is the arm you want to move while watching the gauge. It moves in towards the transom when the motor is tilted all the way up.
 
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