Yamaha bogdown

[Paddleon]

I've read and searched this entire site and definately feel I've gotten a good education on power loss and fuel problems...ethanol and water seoperators....02 sensors and VSTs etc.
Had similar situations with my last boat ( rough running,loss of power...)that had an outboard.That was a 1987 Mariner 40 HP.Easy to work on and I rebuilt carbs and new my way around it fairly well.
But this engine is...much more complicated.2004 Yamaha 150.I'm hesitant to do more than the basics and I'll let a mechanic work on what is over my head.
My problem has to be an easy fix.It feels fuel related and that is where I'm coming from or going to.
Here is my tale of woe:

She has always run like a champ.Sat I go to start her up and it takes awhile.
Hmmmmm...strange as she always starts up fairly easy.
Temps had dropped the night before so I'm thinking this is the coldest I've ever had the boat and maybe its just that...a chilly night after 2 days of rain.
Get her going but the engine sounds odd...a miss/cough/sputter ever 20 seconds or so.
Warm her up and she smooths out but the sputter is still there every 30 seconds now.
Ease her out of the slip and down the canal but turn around after a few minutes because I just don't like the way it feels.
I have a new water seperating filter and after I tie her up I change it.
Start her again and she sounds good to go.
Ease her out and down the canal and still don't like the way the engine is running.She always purred ( as much as a 2 stroke can purr ) and this cat is not her usual self.
I push the throttle to get going and she begins to but quickly bogs down.
Back to the slip I go...
Pull the cowling and clean the engines fuel filter ( it was clean).
Start her and she runs nice!
But bogged down again once I was out and trying to get going

Pull off the cowling once again and it was then that I noticed a rubber hose laying in the bottom not connected to anything.
I'll be damned if I can find where it goes to!
Or if this in fact is my problem :roll:
Hoses just don't lie around ....

I've got a small mirror I'm going to use to try and look under everything.
Unless one of you tells me that this hose is meant to be just like it is.
Thanks for any input you can send along!

 

[TomS]

I have good news and bad news..

The good news is that I'm pretty sure that hose just gets attached to the back of the air intake cover, on the lower right hand side. The air intake cover is that big black plastic piece that covers the front of the engine. Not sure if you can re-install the hose with it still attached, you should see a slightly larger hose also attached to the same spot, maybe follow it back with your fingers. If not, its easy, just unscrew the 5 or 6 screws on the cover (make sure they don't fall out) and re-attach the hose.

The bad news is that I don't think it has anything to do with your engine problem.

Was there anything in the fuel/water separator when you drained/replaced it? Any signs of water in the fuel?

-- Tom

 

[DaleH]

Couple things ...

If not a fuel/water separator with a clear see-thru drainable bowl ... I'd switch to one. When my brothers Yummie 150s act up like this, he has to drain off some crap from the f/w filters.

If you are using closed bowl filters ... this could be part of your problem.

Also check to see that you might not have accidently tripped the manual choke. If you put it ON ... it makes extremely tough starting and running like you stated.

Check too the gap of your plugs, as they wear in ~ 50 hours and need to be checked/re-set.

 

[johnsw]

Seems to be the number 1 question these days: Is it fuel or mechanical? One way that might at least help you narrow it down a bit is to get some clean, fresh gas in a portable 6 gallon tank, connect it to the engine at the primer bulb and run the engine. If the problem goes away, then you're looking for something with the fuel system back from the primer. If the problem doesn't go away, then time to start looking for something wrong under the cowling.

Good luck

John

 

[Paddleon]

Thanks everyone for the sugestions and help!
Heres the latest:

That hose was just disconnected from the bottom of the air intake cover like TomS said.Could have put it back on without removing the plastic air intake cover but took it off to get a better look at the carbs.Its just a vent hose and has no effect on the bogging problem.

Clear bowl water seperator filter installed last Saturday.This is something I've meant to do earlier.I want to see/know when the filter is doing what its designed to do.No more solid filters!
I took Dales advice and pulled the spark plugs.They all looked the same and not in bad shape at all but bought new ones...gapped them and installed them yesterday.
Took her out for a test drive and...
same problem.Idles good but bogs at 2000rpm and above
While I was installing the new plugs a guy from the local Sea Tow walked by and we started talking.I asked him if he had any dealings with Yamaha engines and he said all 10 SeaTow boats he has are Yammie powered.

I told him my symptoms and he said...
"fuel pumps!...change em.... they are overdue and what your describing is what I see on our engines very often"

So I removed the 2 fuel pumps and bought new ones today.I was going to rebuild them but...for $38 apiece I think they are affordable enough to buy the complete package and not mess around.Brand new original Yamaha pumps!
I took the old ones apart and the rubber membranes look well worn.No tears,holes or rips but the top fuel pump membrane looked stretched out and very discolored.
This engine has a bit over 400 hours on her and I'm guessing these 2 pumps are original
Ran out of daylight today but if the weather permits I'll install them Friday.
My gut instinct ( after reading 30 pages of IBoat threads on fuel pump related problems...talking with SeaTow and the parts guy at the local Marine Parts place who over the years has been extremely helpfull!)) says this is my problem.Fuel pumps gone wild.

I'll update and post my results as soon as I go for a spin.
Fishing is heating up and I really don't want to play mechanic when I could be out drifting eel...dunkin bunker and ladling clam chum

 

[Paddleon]

Update...
Installed 2 new fuel pumps on Saturday.Very straightforward and simple.
Started her up and she purred like a kitten.
But...she always idles like that.
Took her out for a test drive and I could tell immediatley that the fuel pumps were not the problem
Underway there is a slight vibration...hesitation.Can't really describe it other than I can tell its not running like it was.
Go to open her up and...bogs down right around 2000.She'll get up to 26--2700 and surge back and forth.

Whats next?
One other problem I'm having is my oil tank on the engine is not recieving oil from the remote tank in the bilge area.
The "emergency" switch on the engine is not working and I had to fill the engine oiltank by hand.
I know there is a filter on the backside of the remote tank that can clog.
Anyone have similar problems with the oil/fuel etc.
Shes mixing oil/fuel but it seems to be using alot for these short test drives I'm taking :evil:

Could my problems be related?Seems obvious...

I'm stumped and out of answers.

On the positive side I've put in new plugs,water sperator filter and brand new fuel pumps
I've also learned alot about this 150 carbed Yammy which fits in well with my brains need to know how things work.
The low pressure fuel pumps are ingenious!!! Amazing how they work!!!

 

[DaleH]

Get some plastic plug wires and put boat tied to dock @ high idle, not to exceed 1500 RPMs. One at a time, pull the plug wires off ... the motor RPMs should drop. If it doesn't on one plug wire, that wire or coil could be shot or worse ... intermittant at high speed.

Surging still sounds like fuel isses though ...

Hey, have you pulled the SCREEN off your fuel tank yet? Use 2 box wrenches and pull the fitting off the top of the tank. I'd almost bet $$ you'll find 'naval lint' all buggered up on the pickup screen. Also see if you have a anti-siphon valve in-line at that tank fitting, it too could be plugged up with CRAP from the fuel.

 

[johnsw]

Does oil transfer OK when the engine is running normally? Oil level shows full (3 bars) on the dash guage? If so, then the sensors, pump, filter and oil lines are probably OK and you might have a bad emergency switch. Easy enough to check with an ohm meter.

I've got the '04 150 also, and the oil transfer under normal running is controlled by the CDI unit, which rarely fails in this regard. For future reference, the oil transfer is first initiated when the motor is started. The CDI will turn the oil pump on for 90 seconds or until the sensor in the engine tank signals it is full and needs no more oil. Once the engine is running, there is a fill level sensor in the engine tank that signals the CDI to run the oil transfer, and it again runs for 90 seconds or until the engine tank is full. If oil transfer never occurs and the low limit sensor in the engine tank senses low oil, the CDI will force the engine into failsafe mode, sound an alarm and it should turn on the oil pump for 180 seconds. If you shut the engine off and restart the engine while the low limit switch is closed sounding the alarm, the oil pump should run for 180 seconds instead of the usual 90, or until the engine tank is full. I learned this the hard way while I was working on my low oil level problem this season. That's a whole other story.

The emergency switch circuit is pretty straight forward. With the key in the on position (engine not running), oil should transfer to the engine tank when you press the emergency switch. It's a direct path to ground for the oil pump motor. If everything is working, you should be able to hear the pump running with the bilge hatch open. If the pump runs but the tank doesn't fill, start looking for an obstruction. If the pump doesn't run, first check your connectors, wiring, switch and ground conections. If everything in the wiring is OK, then the pump could be shot. You can check for continuity across the motor winding ( 4 - 8 ohms) at the connector in the bilge. The wiring diagram in the Yamy manual should show what wires go to the pump.

I wouldn't think the 2 problems are related.

Good luck

John

 

[Paddleon]

Thought I'd update the adventure...
Wanted to thank everyone who has suggested things.I've done just about all of them.

Tuesday I took the day to give it another go and do what I knew would be the final steps before admitting what was starting to become obvious: carbs need cleaning/rebuilding.

I pulled the remote oil tank and cleaned the filter that sits out of view and at the bottom exterior.It was clean but it did give me the chance to remove a bunch of sludge sitting in the bilge area that I could never get to.Similar to pulling out your kitchen fridge and finding massive amounts of dustballs,dog toys and that birthday card from 1982 :roll:
Reinstalled and will come back to the problem of no oil being pumped to the engines main oil tank soon.

I had with me a 3 gallon fuel tank with fresh gas and a new primer ball & fuel lines.I completely bypassed the boats fuel system and hooked directly to the engine.Started her up and she purred (as best a 2 stroke can purr) like a kitten.
But as I've said she always purrs like that when idling.
Lines off and eased her into the canal.
Knew right off that the problem was still a problem
Gave it some go juice and ...boggin like a mule in mud.

"oh well" I thought.I gave it my best and went thru all the steps I needed to.Gotta be the carbs!
Actually I used a few choice words that can not be repeated nor written :evil:

Carbs were removed yesterday by the marinas mechanic.I contemplated doing them myself but without the manual ( its on order...and should arrive soon) there is no way I'll touch them.
I've rebuilt carbs but these have an awfull lot of ports & jets and nooks & crannies,vents and assorted doodads.
I popped in to see them on the bench being worked on and hopefully they get installed today.
Fingers crossed and I'll be doing a little Irish jig on the Parkers "dance floor" if the problem is solved.

Don't touch that channel kids!
The shows not over...

 

[Outta Here]

I'll bet the carb cleaning/re-building will do the trick. You're right, the carbs do have a lot more small passages and holes than traditional carbs. This is 1 reason the carb Yamahas set gas milege records. Way more economical than the competition.

I had a similar problem w/115-2. After carb repairs, try using some simple, cheap Wal-Mart "Carb or FI Cleaner". Around $1.00 for bottle to treat 20 gallons. It worked for me.

 

[DaleH]

Carbs were removed yesterday by the marinas mechanic.I contemplated doing them myself but without the manual ( its on order...and should arrive soon) there is no way I'll touch them.

I've rebuilt carbs but these have an awfull lot of ports & jets and nooks & crannies,vents and assorted doodads.

Great idea to run on that 3-gallon tank to isolate the fuel source/delivery as a possible issue.

Re: carbs, good idea to wait until you have the OEM service manual. Too many don't realize that there is a proper sequence to flushing out a carb (i.e., rinse smaller orifice into larger ones and then out of the body), otherwise you can drive crud in deeper. Also note that there are fine ports and orifices in the inlet manifold, which is the large plate the carb body bolts up to.

 

[johnsw]

I guess that's progress. You've narrowed the problem down to the top of the engine. Tough to say if it's fuel or ignition related since it's seems to be a high rpm only problem. You've done the fuel pumps and now the carb's will be checked out. Hopefully, that will be the problem.

I'll throw this out there and we can kick it around a bit (or not). Did the oil transfer problem start the same time as the performance problem? I wouldn't think they'd be related, but they do have the CDI in common. When the engine goes into failsafe mode controlled by the CDI, RPM is limited to about 1800 which if I read your post correctly, is about where you bog down? CDI failure is rare, but it can happen. If the carbs don't fix the problem, you might want to post your problem on yamahaoutboardparts.com and see what feedback you get there.

John

 

[Paddleon]

Yes...both problems started at the same time.
You may be onto something as I just got off the phone with the mechanic a few minutes ago and...
there will be no dancin the Irish jig today
Carbs were put back on and still boggin.
I called him back after I read your Post John and he says that is where he was headed next...CDI.

to be continued...

 

[Paddleon]

Another thought for a rainy Saturday in October..

The trim gauge has always blinked at the very top line.Been like this since getting the boat in April.
Never gave it much thought.She ran fine till a few weeks ago.Engine up or down...solid lines to the blinking top one.

I posted my problem on the yamahaparts.com sight a few minutes ago.
Almost word for word thanks to copy n paste

I'll tell ya what tho...
I've learned more about this boat/engine in the past few weeks than I ever imagined!
Thats a good thing and I'm looking forward to helping others when I can now that I'm edumicated and a learned

 

[johnsw]

It's never easy.

Checked the wiring diagram for the trim circuit, and looks like the trim sensor goes directly to the gauge. Your blinking segment might be a gauge or sensor problem? Maybe the sensor isn't quite in the proper alignment so it's not giving a true, full up reading? Or maybe the sensor resistance is off a bit? But I'd check the alignment first. You can probably tweak the sensor position on the bracket or the little arm that's on the motor pivot that rubs against the sensor arm. You might find that full up position on the sensor has a bit more to go and that might be enough to stabilize the gauge reading.

Good luck

John

 

[TomS]

Keep in mind that on some model years/models, the engine wouldn't transfer fuel from the remote tank to the engine mounted tank if it thought that the engine was tilted up. So, if your engine falls into this category, and your trim indicator is blinking like the engine is all the way up, that would explain why oil isn't being transferred to the engine tank.

Most likely the engine trim ring is gummed up and can't move freely, spray it with some WD40 or something similar and see if you can work it free. Chances are it isn't stuck, just gummed up a bit.

-- Tom

 

[johnsw]

Yes, earlier Yamy's used trim angle to prevent oil transfer from happening. But that was changed sometime prior to 2004 (1996, I think). With these engines, the oil transfer control uses the engine timing signal to determine that the engine is running, eliminating the trim sender information needed for the the oil control system. Yamaha called it their SMART Precision Blend System. Regular oil transfer (not using the emergency switch) will only happen if the engine is in fact running. Oil transfer will be enabled by the CDI as long as it gets the timing pulse and all of the sensor levels are correct.

John

 

[Paddleon]

Update: 11-5-2007

I'm at a loss on whats wrong :evil: and its now in the hands of the yards mechanic.

I pulled the remote oil tank and checked the oil pump.It was not working and connecting directly to it produced nothing.Checked all the switches and gizmos that work the oil sending and everything worked...but the small oil pump in the remote tank.Took it back to my garage and completely emptied the tank (figured since I had it out I would thoroughly clean it)and removed the oil pump & small filter.
Replaced both with brand new and reinstalled the tank...
Works like a charm and I now have oil being sent when its supposed to be sent Emergency oil switch and the entire kit n kaboodle is A-OK
The tank is as clean as the day it was first installed.There was a slight bit of crud and gunk in the bottom but not much.Old filter was fairly clean but I knew that from when I removed it 2 weeks ago.

Next I tackled the trim sender and that was just a quick adjustment of the unit on the engine bracket.Digital readout now functioning like it should

Took her out for a test run and...same old same old.

Thats it for me! Things are now officially "over my head" and it needs to be hooked up to a machine that can read the CDI or something like that.
Stay tuned! I'll post the final verdict and repair.

 

[TomS]

Thanks for the updates, and please keep them coming! Good luck, hope its something simple..

-- Tom

 

[Paddleon]

Update...
Sadly there is nothing to report
We've switched mechanics to a person more experienced with Yamaha engines.
I'm curious on what this will wind up being...
and costing :evil: