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Post by Juan on Jun 28, 2017 17:32:33 GMT -6
A couple weeks ago my 04 Yamaha F-150 outboard started losing power at about 2,000 rpms and an alarm sounding when it lost power. I found two of the four spark plugs only finger tight, so I replaced them with new ones hoping that solved the alarm problem.. Well today, I found out it didn't help and I still have the problem and would appreciate any and all suggestions as to what may be causing the problem.
Here's what it's doing: It idles fine and runs fine until I throttle up and it reaches about 2.000 rpms.. At that point the alarm sounds and the rpms drop to an idle speed then the alarm goes off. When the alarm goes off I can drop the throttle back to under 2,000 rpms and she runs fine at that speed with no alarm. If I try to throttle up again, it jumps up and runs fine for a second or two then the alarm goes off again so I can't run over the 2,000 rpm mark. It's shooting water from the pee hole and it looks to be normal but I don't have a pressure gauge so I can't tell for sure if it's passing enough water. I replaced the water pump at less than 100 hours ago.
I'm guessing and hoping it's an over heating problem and the alarm is causing the safety mode to kick in. I plan to change the thermostats and the water pump again just to be on the safe side. I'm also going to add a water pressure gauge but I'm wondering if the loose spark plugs could have caused a problem? I'm considering buying a compression tester but not sure I need to since it seems to run fine at idle and for a few seconds at WOT until the alarm kicks in.
Anything else I need to check or replace? Could the coils cause this?
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Post by gnrphil on Jun 28, 2017 18:12:22 GMT -6
Could be engine oil level, water in the engine fuel filter, clogged oil filter,oil feed/injection pump, cooling system. when was the last service?
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Post by Juan on Jun 28, 2017 18:28:54 GMT -6
Could be engine oil level, water in the engine fuel filter, clogged oil filter,oil feed/injection pump, cooling system. when was the last service? Can't remember exactly but the last time it was in for a full service was probably 4 years ago + or -. I changed the fuel/ water separator and checked the fuel filter under the cowling... no water at all in either. Oil level might be too high if anything... could too much oil cause it? Does a 4 stroke have an oil feed/injection pump? |
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Post by gnrphil on Jun 28, 2017 19:14:56 GMT -6
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Post by Juan on Jun 29, 2017 10:33:32 GMT -6
Thanks for the suggestions guys. I really appreciate it. I think I may have found the problem. I pulled the thermostat out, ran it in the cattle trough and the alarm stopped. It seems to run fine without the thermostat. There was a little piece of what looked like gasket material in the thermostat spring and I suspect that may have been the problem. I used a torch and heated the thermostat and it opened but I think it took too much heat to get it to open so I've ordered a new one.. Now another question:
Can a bad thermostat cause premature wear on a water pump impeller? It's peeing, but I don't think the stream is as strong as it once was and I'm wondering if the water pump impeller could have worn because the thermostat wouldn't let the water circulate as it should. I replaced the water pump 2 years ago and it shouldn't be worn out yet but I guess it could be.
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985crabs
Captain
2000 V1900 Bay Series, Yamaha 150 Carb. 2
Posts: 1,309
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Post by 985crabs on Jun 29, 2017 11:44:40 GMT -6
I don't think the stream is as strong as it once was... Ain't that the truth. See Cross's comments above. I think you'll know a lot more when you put that water pressure gauge in whether your flow is adequate or not. If it's been a couple years since you changed your impeller, why not do it again? I know you like to wait until it's fossilized, but if you ran it for a while with the new gauge and old impeller, made not of the operating range, then changed the impeller you'd see if it made any difference or not. With heat, corrosion and friction being the natural enemies of your motor, it's an easy fix if you're concerned. |
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Post by gnrphil on Jun 29, 2017 12:15:13 GMT -6
I don't think the bad thermostat would have any adverse effect on the impeller, you might want to look at the poppet valve also.
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Post by Juan on Jun 29, 2017 12:40:34 GMT -6
I don't think the bad thermostat would have any adverse effect on the impeller, you might want to look at the poppet valve also. Okay, save me a week of Googling... where the hell is the poppet valve?  |
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Post by Juan on Jun 29, 2017 12:46:12 GMT -6
I think you'll know a lot more when you put that water pressure gauge in whether your flow is adequate or not. If it's been a couple years since you changed your impeller, why not do it again? I know you like to wait until it's fossilized, but if you ran it for a while with the new gauge and old impeller, made not of the operating range, then changed the impeller you'd see if it made any difference or not. With heat, corrosion and friction being the natural enemies of your motor, it's an easy fix if you're concerned. I'm changing both the thermostat and water pump and installing a pressure gauge if I can figure out where it connects to the block. |
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Post by gnrphil on Jun 29, 2017 12:47:10 GMT -6
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Post by gnrphil on Jun 29, 2017 12:48:18 GMT -6
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Post by Juan on Jun 29, 2017 16:02:44 GMT -6
Thanks Phil. I'll check it out.
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Post by freezerfiller on Jun 29, 2017 18:00:00 GMT -6
yeah, I think your impeller is fine. I don't suspect that a stuck thermostat would cause any issues as it is closed until it gets hot enough every time you head out. replace the t-stat and see what you get. It seems like your engine is going into limp home mode which should go away once you solve the problem. Next time use boiling water instead of a torch, and you can re-use it if its good.
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Post by Juan on Jun 30, 2017 5:17:54 GMT -6
One of the guys on the Band of Boaters site says that running without a thermostat might cause a weak pee stream and since the new thermostat is due to arrive ahead of the water pump, I think I'll install it and check it out before I pull the lower unit to change the water pump. I'd like to get more than two years out of the water pump so if it's not damaged, I'll have a spare on the shelf for when it needs changing.
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Post by Juan on Jul 2, 2017 8:09:21 GMT -6
Well a new thermostat didn't help. At this point I don't know what else to do. I'd take it to take it to the shop for repair but there are only two local shops that are Yamaha qualified and I refuse to take it to one of those (that's another story) the other is two months behind and I really hate to be without the boat that long...(plus I'd have to remove the trolling motor and everything in the boat)
I checked the temp with a temp gun and this is what I got:
Cold temp : 78º
5 minutes at idle: 120º
4 minutes at 2,000 rpm: 134º
3,000 rpms: immediate ALARM I took the temperatures on the block in two places... (just above and just below the coils) Are those temps within "normal" range?
It started peeing immediately at crank up and the steam now seems to be as strong as ever so as freezer advised, I doubt the water pump impeller needs replacing and the poppet valve looks good. I disconnected the sensor at the thermostat and still get the alarm so I guess I can rule out a bad sensor. I found out how to correctly check the oil level and removed about a quart of excess oil so now it's at the right level on the dip stick. . I'm going to check the compression next but I don't think that's the problem. Is there a way to check the oil pump and pressure? Could the alarm be an oil pressure problem?
SC: The bulb pumps up and holds and there's no indication of fuel in the crankcase.
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Post by freezerfiller on Jul 2, 2017 9:36:15 GMT -6
Do you know what temp the thermostat is supposed to open? Mine runs at 130. Usually, if you have a low oil pressure alarm, it will happen at idle, not at higher rpms. I think you need a little more data.. What if you run it at 2000 for 8 minutes? Temp still at 134? I would do that first to elimate the temp issue.. I'm betting it's either a fuel pressure issue or a coil issue. Is this an HPDI engine?
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Post by Juan on Jul 2, 2017 10:40:34 GMT -6
It's an EFI engine. I haven't run it for 8 minutes at 2,000 rpms in the tank but did when it acted up on the last fishing trip. I had to idle back to the ramp and it ran fine at and under 2,000 but much more than that would cause the alarm and safety mode. Not sure about the operating temp but from what little I can find online, 130 is actually on the cool side and since I can disconnect the sensor and run it without the thermostat, I'm guessing the cooling system is working and it has to be something else causing the alarm.
Is there a way to check the coils?
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Post by Juan on Jul 2, 2017 17:12:46 GMT -6
A quart of oil is a good bit over. Problem is that gas mixes with the oil and thins the oil. It is very hard to to detect just by smelling and feeling oil if gas is in the oil since both are petroleum products. I still think you have a low pressure fuel pump issue, but not certain that is casue of your alarms and safe mode, could be. I know 4 strokes can make oil from running to cool and idling to long, but not that much. Regardless an idiot light or alarm going off doesn't help much. These engines are so computerized knowdays I think you need access to what the computer codes are saying and why alarm and safe mode is kicking over. Could be yammy's have an oil level alarm. I see no other way than taking boat to a mechanic. Maybe they can hook it up and see if its a quickfix. Either way see if they have a low pressure fuel pump in stock. You probably need one anyway. BTW my low pressure fuel pump was leaking for a long time and bulb would hold just fine like normal operation. It was not until engine started acting up like it was starving for fuel that fuel bulb would lose prime after a bit. Also you can check your low pressure pump yourself. Its just bolted in. You can probably take it out and check in less than five minutes. Put pressure on bulb and then press the piston that is bumped by cam a few times and see if any gas comes out. Thanks. You may be right about the low fuel pressure and I'll certainly try to find and check that. I'm leaning toward a low pressure oil problem since I understand the alarm will sound for only two reasons... either high temperature or low oil pressure and now I've about ruled out an overheating problem. Did you have an alarm with your fuel problem? I also don't believe it's making much oil and the excess oil was actually my fault. I've had this motor for over 10 years and didn't know that there was a special way you have to check the oil in 4 strokes. I do now. Yamaha actually has a video on the subject. In short, you have to tilt the motor up, let it sit there for at least 5 minutes, tilt it back down and then check the oil. I didn't know that and have been over filling it since day one. I know the easiest way to find the problem is to take it to the shop but the local shop here has ripped me off twice (once ended up taking them to court) and has a two month waiting list. I may have to swallow my pride and take it to them but I'd like to find and fix the problem myself if possible and if it's a problem I feel comfortable tackling. |
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Post by Juan on Jul 3, 2017 5:52:15 GMT -6
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mosquito13
Lieutenant
Posts: 788 
Location: the other West Coast
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Post by mosquito13 on Jul 4, 2017 7:53:43 GMT -6
dropping the lower unit is easy and you can check the condition of the water pump and impeller. got a temp gun(infra red type for 30 bucks at harbor freight) . If you suspect restricted passages I have had good luck with diluting a marine scale dissolver 50/50 and putting 6 gallons in a heavy duty garbage bags 3 layers of bags and running/flushing the motor til heats up . Let sit for a half hour and run again til heat up. A golf t in the pea tube ... then flush with fresh water in a big way . I have a cattle trough for flushing so I run up to 4 four thousand rpm . I will look for the name of the product I use(but their is a bunch on the market), it is billed as not harming metal. I dump it in my tank after the concentrated flush . Be surprised at how much chunky crap comes out. Learned this trick after overheating problems on a evinrude. Do not tie bags on lower unit ... have two helpers hold the bag on each side or you will learn how much air you engine pushes. Learned that the stupid way. Doesn't the new motors have a computer mech can hook up to to find out what sensors wear setting off the alarm? If yours has , that would be my first step. Hammerhead marine descaler
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