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SLOW. Maybe?

K

keithm

Contributing Member
1987 xp150 premix. 100lbs compression all 6. Strong spark 7/16 gap bright blue. Carbs newly rebuilt. New water pump.

Started up. Idle was fairly smooth but a little high. Went to half throttle very smooth went to full throttle again very smooth ran for about ten minutes at about 3/4 throttle suddenly lost power. I checked tank vent it was open and clear checked fuel bulb it was firm. It never died i went to idle it was fine. Went back to full throttle ran greatafter about 20 mintues i shut it down. 2 hrs latter started back up, let it warm up about 5 minutes. Went to full throttle it would only take half. Loaded up went to the house and rechecked everthing i mentioned above.

When i turn on the key i do get the tell tale alarm. So i know it funtions
Should i disconnect the temp sensors and see if it still does it?
I did notice the tell tale stream of water the exhaust was extremely smokey
Im running fresh gas with 50:1 mix on a six gallon tank with a 3/8 line.
Im wondering if its in slow mode and the alarm is not sounding or did i somehow get some trash thru the filter into the carb.
 
Compreasion numbers 100 across the board. Spark jumping a 7/16 gap bright blue on all 6Plugs only have about an hour on them so they are just starting to show color color is coffee with 1 creamQl77jc4Lower unit oil is fresh. No signs of waterBtw way what is the red lever on the choke solenoid
 
Update, the throttle plates are opening all the way, I used a much more accurate compression gauge, the readings varied slightly, left bank 110 ,110,102 right bank 105,105,105 as above the sparks are bright blue and jump a 7/16 gap. As for the choke it really doesn't have one per say, it has the solenoid, I must say I am not familiar with how it works. One of the local techs mentioned that the vro could be weak. I'm running on a 6.6 gallon chilton tank. Is there enough flow thru that quick release fitting. I'm grasping at straws here.
 
I happen to have a standard pump from a 1976 85 hp Johnson, would that suffice. Is there enough volumn from this pump to fill 3 carbs. Do I remove the pulse limiter when doing this conversion?

ill check out the vro and the the pulse limiter first.
 
If tach wire is broken would that have any effect on vro, I just found an intermittent connection at the plug on the throttle control box.
 
Something I totally forgot about when I was at a steady pace just above idle I could feel a very slight surge that didn't seem present at higher speeds, if the solenoid was seeping that could explain that also. I was telling a local about that. He asked if I had moved the red lever, I said yes,at that point he said replace the solenoid because you never move the lever. Seems a little extreme to me. I'll start it up a little later and pull the line and see if it's seeping. Thanks again for the advice
 
I have mounted the fuel pump and removed the vro. Local tech said he's seen this done with no problems. I was looking at the 83. 150hp. It actually has two fuel pumps in series. If I understand it correctly if it maintains 3 lbs your good
 
The 150 had a pulse nipple in the block, with an inline pulse limiter, I just put a short pulse line on it. Weather got bad here so I'll head to the lake in the morning.
 
Lake test was interesting. After installing standard pump engine started and idled well on hose. At the lake started easy popped for a second or two. After a thorough warm up idle was almost smooth. Once out of the no wake zone I eased up to full throttle at about 2000 rpm it quit accelerating, had a miss like a couple of cylinders went down then came back, or loaded up, then all at once it came on and wow did it move, I eased it back to 3000 rpm and just cruised about 50mphran well for about 30 minutes at which point I headed back to the dock to pick up the wife. Idle was smooth and reliable, once she was aboard, we headed out to see if all was well. Once out of the no wake I hit the throttle it came up to 1800 and that was it I checked fuel bulb, very firm, tried backing off and on, 1800 was as good as it got. Shut down and checked all the plugs tips were dry and color was dark brown plug on number 4 had a little gas down in it. After reinstalling I disconnected the temp sensors. There was no change 1800 was as good as it got, reconnected sensors and headed to the dock. Dropped wife off and tyre done more round. Idle still
smooth would accelerate to 2400 rpm so once again headed to shore. All at once all 6 hit and then shut back to 2400 again. I now have the carbs off and am looking to see if I have dirt in them. The only other thing I know at this time is to replace the plugs. Any ideas I'm about out of options. After looking at these carbs I guess it's off to chapter 3 for electronics
 
Carbs looked great extreme clean. I started the engine on the hose and it ran well at idle I brought the idle up to 1800 and developed a terrible miss. I then did a iratic spark test and found the starboard bank was indeed irratic.
at this point I either have a stator issue or a power pack. All coil readings were identical and in spec. I still need to do an ac voltage test on the stators starboard bank. I'll do that test and let ya know
 
Here's something interesting, the starboard bank that is cutting out checks 950 ohms. Within the spec.
the port side is 745 well outside the spec, that is the side that is working. Now the port side does have a new power pack the starboard does not. I have another stator. I'll check to make sure it's in spec. If so and I change it out if that problem persists would it make sense to swap the power packs and see if the problem follows the pack.?
 
Ok the stock stator had the 950 starboard and 745 port. According to all the specs they should be 900 to 1000.
the ports side is out of spec but yet it works. I pulled a new stator out of the box just to see where it was. 545 ohms on both sides. I swapped the packs and the problem followed the pack. There is no voltage on the black/yellow wire on either side. When I turned off the switch while running one side shut down the other didn't .
obviously the power pack is bad, the stator at present is working. So what do you think replace the pack.?
 
Wow a lot going on.
ok ohms check while plugged in on the brown and brown yellow wire , dropped 30 ohms on each side so 725 and 930.
so would that confirm a bad stator at this point? And of course the power pack that took the intermittent with it?

stator voltage was 90 on port and 130 on starboard while at idle they did fluctuate a little but only a few volts plus or minus.
 
so how do i tell the difference from a 9 amp and a 35 amp?
any idea why it wont turn off now that i have swapped sides with the power pack, rpms drop like one side shut off. i have good contact on black yellow leads, maybe the PP?
ill get that info and get back with you this evening.
 
just need to clarify, one trigger has brown yellow wires, the other side has 2 brown wires, im looking for ohms between 1 side brown and the other side brown yellow' looks like the difference in the stators is the 10amp has trigger straight across from each other 35 amp triggers are right next to each other.
 
Model e150stlcur
rt side ohms 950. Br/y to br/y
lt side ohms 750 br to br
i reassembled and started at idle 13.8 volts at battery. 14.7 at 3000
What are the connections with multimeter to check dvm
 
I was running thru the troubleshooting guide 113-3114. Intermittent spark procedure. Step 1 the first three checks were 12.6 ohms both sides. 86 volts on right side 72 on left. Step 2 revealed .2 volts on all six cylinders they did fluctuate a little to a max of .6. Wow this is frustrating looks like the only thing working is the regulator.
 
The stator that's on the engine looks just like the one in the picture. The flywheel is the same as the first. In the motorcycle industry we call the driver coils, source coils or pulser coils. The dva chart on CDI sight show the trigger coil resistance in range. I'll recheck the dva outputs (orange wires)in the morning. I assume I need to ground plug wires when cranking.

Thwhen I shut down the engine one side sounds like it continues to run, switch the key back on rims come up. The black yellow kill wires go to the key switch and then ground?

ive ordered the pp, hesitating on the stator till I have more info
 
The newer pack is the one that is shutting down when switched off. That older pack is the one that that is intermittent. I'll wait till the new pp arrives, then run thru the checks again.
 
Got the new pp. Went thru every test in the cdi. Troubleshooting guide with the exception of the dva because i havent started the engine. The only problem ive found was one side of the stator is 750 ohms instead of 950 to 1100. Before i actually start the motor is there anything else i should look at. Im hesitant because in the marinw idustry one thing wrong in electronics can take out 3 more thing in the blink of an eye. In powersports we rarely have that problem. Systems are more protected from each other
 
UPDATE: I received the new stator today. I double checked the resistance and found it to be on the money.
i have hooked up everything including cleaning all grounds. I think I'm ready to fire it up. I found something I hadn't noticed before so before I start up I wanted to ask. When I removed the old stator below the drive coils there was a black gooey substance, it appeared to be the sealant they used on the drive coil,I assume if that is what that is the stator has gotten hot. Is there a test I can do on the regulator? And the other thing is is it a regulator/ rectifier or just a rectifier?
 
I have a fluke 77 with a dva peak adapter, when I check the output to the coils,for example, I set the meter on dc, install the dva , positive lead to the orange wires and black lead to ground. Start the engine and see what I have.

is that correct?
 
update: Started it up with power pack on starboard side replaced and new stator. Unit still only runs on port cylinders. So I swapped side with the power pack. Now it runs on the starboard side port side has no spark. That would seem to indicate a bad power pack.

I also think there there may be a problem in the kill wire. When the good power pack was on the port side the switch would shut it off, when I moved it to the starboard side the kill circuit didn't work, I think this would indicate a break in the black yellow wire on the port side.

btw. Dva. Was showing 205 volts on the orange leads on the good power pack
 
PROBLEM SOLVED. At least its looking good. I found the ground issue was the male amphenol connector was broken inside the rubber insulator which got me to thinking about the power pack lead going to the stator i found the same issue. I never saw it before because i always back probed the connectors. Lesson learned. Good thing is i have a spare power pack and i did find the stator out of spec. Lake test tonight ill let you know how it goes
 
Lake test went well, warmed engine up , backed out opened throttle engine ran clean all the way to 5300 at that point I had to back off way fast. Only issue was fuel pump leak, I'll fix that in the morning. Thanks for all the help and advice. Learned a lot on this one. Unit has a slight shutter at idle but I think that will clear after it runs a while.
thanks again.

keith
 
Yep. I gotta admit. When your flyin and ur only at half throttle there is something about opening it up that is exhilirating. If i see an issue with 15 volts ill run thru the tests for the regulator again. Probably wouldnt be a bad idea to put a dash mount volt meter on it. If that does go over 15 would it help to turn on evey accessory i have?
 
Ok day on the lake. Voltmeter never read higher then 14.93. Motor ran good. Way more power then the 85. GPS showed 70. Before I backed out. Big thing I noticed was at 900 rpm idling in , a little bit of noise in the bottom of the motor drained lower unit no water oil in good shape. I should say sounds more like under the boat not the motor.
 
Keithm
So if you dont mind me asking what was the main problem for the engine going into slow mode cause mine is doing the same thing. I have replaced the power pack and the rectifier/regulator and also the spark plugs. also replaced the water pump and the temp sensors and the thermostats and also cleaned the water passages behind the heads. for a whle it was an overheating problem but that prob resolved and now my engine definate still goes into slow mode once it has reached 5500 rpms after 45 secs of WOT.
 
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