OMC tech: No power, another rookie without a clue!

**racer** · 05-16-2017, 09:07 AM

If it is going into slow it will be somewhat smooth right up to 2500 then it will shake bad if you leave throttle open trying to go up but if you back off to say 2300 it will smooth out again. Do you have a tach with 4 lights and are any on?

**93hydrasport** · 05-22-2017, 06:55 PM

only had a couple of free hours this weekend so wasnt able to do much with the engine. I had a "spare" shift switch and being as easy as it is to swap I just went ahead and did it. before I did that all I had to check spark was an inline spark tester "harbor freight cheap" BUT i have spark on all 6 as it idles on the hose. I failed to slip it into gear as I was testing each for spark tho (kicking myself for that now) when I got to the loading ramp, I had to just load and get out of the way. Lots of people on the water this weekend! It fired up and seemed to have a miss. a slight knock or pop and it shook or jerked each time it did? I put it into gear and it stalled. (maybe the spare switch was bad)? of course I didn't bring the other one with me...Sigh.
I cranked it up and let it idle a bit before trying again but it just died. it cranks right back up but wouldn't run once in gear. I used the trolling motor and fished a bit while waiting for the loading ramp to clear. tried again and the same. it just stalls. The tach doesn't have any lights, its the basic Sierra aftermarket plain ole tach. I have a box of electronics and wires I picked up from Instigator when I bought the power head from him... I almost want to just start swapping parts and see which one causes a change! but then again I can't guarantee they are all good! lol I've already swapped the shift switch back (both would shift into gear on the hose) but know the backpressure would play a big factor if only running on 3 cylinders.

**93hydrasport** · 05-23-2017, 07:00 PM

Stoped at the store on the way home today, taking tomorrow off even though it's going to be raining I picked up a spark gap tester and a cheap multi meter... have the boat under the carport and the hose ready, will be checking for distance of arc and if it fires on all 6 when in gear. If it has good spark in both situations I know I can't take it to the lake to load test it. Any suggestions on what to check next would be appreciated!
I suppose I should have picked up a set of spark plugs as well, will have to do that in the AM. The neighbors will probably appreciate the delay in me firing up the engine under the echo chamber of a carport anyway! Lol

**flabum1017** · 05-23-2017, 07:25 PM

have you checked the compression? You will need a DVA meter or adapter to check ignition voltages, but you can do ohm tests with the multi-meter. If you think it's the shift switch, you can run with it disconnected for testing; it will be hard to shift out of gear and find neutral though. Get a fuse puller and pull one plug wire off at a time with it running and put it back on, should hear it miss with wire off and get an exhaust pop when put back on, you can find the culprit cylinder this way. Then it's either fuel or spark. Also, look under the flywheel and make sure all the magnets are secure and evenly spaced, while you're at it, advance the throttle and make sure the timer base is advancing to it's stop and back.

**93hydrasport** · 05-23-2017, 08:10 PM

Originally Posted by flabum1017

have you checked the compression? You will need a DVA meter or adapter to check ignition voltages, but you can do ohm tests with the multi-meter. If you think it's the shift switch, you can run with it disconnected for testing; it will be hard to shift out of gear and find neutral though. Get a fuse puller and pull one plug wire off at a time with it running and put it back on, should hear it miss with wire off and get an exhaust pop when put back on, you can find the culprit cylinder this way. Then it's either fuel or spark. Also, look under the flywheel and make sure all the magnets are secure and evenly spaced, while you're at it, advance the throttle and make sure the timer base is advancing to it's stop and back.

Sounds like a good place to start! Thanks... Now I have to admit I have never pulled a plug wire on a running motor, are these the "Fuse Pullers' you are referring to?

**flabum1017** · 05-23-2017, 09:01 PM

yup

Originally Posted by 93hydrasport

Sounds like a good place to start! Thanks... Now I have to admit I have never pulled a plug wire on a running motor, are these the "Fuse Pullers' you are referring to?

**flabum1017** · 05-23-2017, 09:07 PM

Also, you will want to replace the water pump impeller too, 4 years old is way past due.

**flabum1017** · 05-23-2017, 09:17 PM

That 2500 mark, as Racer said, it where the S.L.O.W. kicks in. The things that will cause it to kick in are overheating, fuel restriction and lack of oil. Since there is no V.R.O., then the only two that are left is overheat and fuel restriction. Originally, the fuel line had a tee before the V.R.O. pump that led to a vacuum switch. This vacuum switch would kick in and activate the S.L.O.W. when there is too much vacuum (restriction). You said you tried it with the temp senders disconnected, so that rules out overheat. I have seen a shorted warning horn trip the S.L.O.W. too, does the horn beep when you first turn on the ignition?

**phillnjack** · 05-24-2017, 07:15 AM

ok now there is one other little thing that can cause a problem.
I had this on my 3 cylinder but it might also be on the bigger motors.
on the top at the back of mine where wires had come from the vro, there is a little diode things that is supposed to be a one way type of thing.
I am no way any good on electrics at all, but I was having similar problems.
I got told to take the diode out, even though my vro was completely disconnected. I did not do anything else and the problem vanished.
it could simply of been pure coincidence I dont know, its just a thought, someone else here will know a lot more about that than me.
.

**93hydrasport** · 05-24-2017, 09:20 AM

Originally Posted by flabum1017

That 2500 mark, as Racer said, it where the S.L.O.W. kicks in. The things that will cause it to kick in are overheating, fuel restriction and lack of oil. Since there is no V.R.O., then the only two that are left is overheat and fuel restriction. Originally, the fuel line had a tee before the V.R.O. pump that led to a vacuum switch. This vacuum switch would kick in and activate the S.L.O.W. when there is too much vacuum (restriction). You said you tried it with the temp senders disconnected, so that rules out overheat. I have seen a shorted warning horn trip the S.L.O.W. too, does the horn beep when you first turn on the ignition?

Come to think of it...No! The warning horn hasn't beeped or "chirped" at all! I think I remember reading somewhere if I ground one of the brown wires to the temp sensor it should make the alarm sound off... is that right? I've read so many posts on here lately it's all starting to run together. LOL

just came in from testing spark, (haven't gotten new plugs yet) I used the spark gap tester on all 6, #2 didn't jump the 1/2" gap. I pulled that coul and swapped it with #3 to see if the problem followed. It didn't...they both jumped the gap after I swapped them? But while checking #3 I noticed spark jumping from the #5 plug boot to the base of the spark plug! Wouldn't have seen it if I wasn't under the carport in the shadows. Had a spare set of wires so changed them and saw no more arcing. Would one shorting wire be enough to cause the problem I'm having ? I'm headed to the store now to get new plugs!

**pbxcomm** · 05-24-2017, 09:25 AM

I believe it has been mentioned.. Before swapping parts, perform a compression test.

**93hydrasport** · 05-24-2017, 09:41 AM

Originally Posted by pbxcomm

I believe it has been mentioned.. Before swapping parts, perform a compression test.

yes it has, and will be doing that as I change plugs. Pretty sure he auto parts store has a loaner tool program since I don't own a compression tester.

**93hydrasport** · 05-24-2017, 10:50 AM

New plugs installed QL77JC4's all gapped to .03
did my compression test with all plugs in, wires disconnected and isolated as to not cause an arc water running to not cause further damage to impeller results are:
1-91
3-90
5-86/87
2-90/91
4-90
6-85/86
Started a little rough after finishing but assume that is from the fuel soaked plugs. The miss I "think" I was hearing isn't as noticible or maybe I'm just trying to think positive!

Alao unhooked throttle linkage from the hotfoot so I could check timer base/trigger movement. It looks as if it moves freely from one stop to the other as I advanced the throttle with the engine NOT running.
With the engine running if I manually move the trigger linkage the timing noticably changed and advanced. I didn't pull the flywheel to check magnets as if yet, but didn't see any sign of the stator oozing onto the block or trigger. If it wasn't such a crap day and raining I would be on the way to a ramp to test it under load!

**flabum1017** · 05-24-2017, 11:09 AM

Did you get spark back on #3? If not, the timer base is suspect, do an ohm test on the timer base (better to do a voltage test, but you don't have the proper tool for that)

**93hydrasport** · 05-24-2017, 11:20 AM

Originally Posted by flabum1017

Did you get spark back on #3? If not, the timer base is suspect, do an ohm test on the timer base (better to do a voltage test, but you don't have the proper tool for that)

Yes I had good spark on both 2&3 when I swapped coils. Maybe I wasn't grounded well when I initially checked #2?