Problems with my Johnson outboard

[Eric_Michael]

Hey Guys,
  I took my boat out for the first run of the season over Memorial day, back on its home waters in Puget Sound.  Ran great!  As always, I brought it home and flushed everything out real good.  This time letting it run on the muffs for a good half hour since I had been on the salt.

  Yesterday I took it out on the Willamette here in Oregon.  I got out of the no-wake zone, brought it up on a plane, and started scooting along.  About 30 seconds later I heard the alarm start to beep, so I immediately backed down.  Boat idles & starts fine.  Got back up on a plane and about 3000 rpms, it starts to buck & miss.  Strange.

  I checked the squeeze bulb.  Soft.  Pumped it up.  Start out again, runs great up to 5k rpm for 30 seconds.  Then starts to buck & miss.  Shutdown.  Squeeze bulb.  Repeat, same symptoms.  I was able to duplicate the problem by revving the engine in neutral.  So I turned around and headed back to the dock at port speed, feeling lucky the problem was apparent before I got too far out.

  Ran over to Wal-mart and picked up a 2-cycle squeeze bulb.  Went home and replaced the bulb.  No luck.  And the old bulb seems good - check valve is functioning.  The squeeze bulb will go soft just sitting after about 15 minutes or so, requiring two squeezes to firm back up.  I don't remember it doing that before.

  My gut check says I am having a problem with fuel delivery, possibly the fuel pump is going out.  I would really like to hear the thoughts of the rest of you.

  Motor is a 1992 Johnson 175 Fast Strike.

Thanks,
-Eric

[Rich_V174SS]

I would first check that the tank vent is open and clear and if you have a fuel valve make sure it's open and there's no restrictions in the line to the engine. Also check air leaks at any of the fuel fittings or filters and for any clogging of debris at the pick-up screen in the tank if it is so equipped. Then look into fuel pump. Does your engine have a VRO pump? If so that could be your problem. I've replaced several that had problems with pumping fuel, good ol' ethanol!

[Eric_Michael]

Yeah, that was one of the first things I checked on the fuel tank.  I had this problem once before.  The tank overflow burbs over the side and makes a mess of the boat when towing between the gas station and the boat launch.  So I usually stick a piece of duct tape over the vent.  Once I forgot to pull it off when launching.  Same symptoms.

Yes, I have a VRO system.  And I am suspicious of the ethanol as well.

How tough is the repair on the fuel pump / VRO system?  Is it a DIY project, or hire the pros?  I am mechanically capable on my cars, etc, but I have not touched a boat motor mechanically.  I don't want to screw this up and make it worse.

Thanks,
-Eric

[Rich_V174SS]

Changing out a VRO pump is easy depending on where and how it's mounted. The only problem is they're around $400 these days. BRP used to offer a diaphragm or rebuild kit but I'm not sure if they do anymore, I think they want you to replace the whole thing. They come as a kit with different fittings so they can be used on several different engine models.

The tank overflow burbs over the side and makes a mess of the boat when towing between the gas station and the boat launch.

Another thing to check is your vent hose. Check to see if it is hanging anywhere in the boat in such a way that fuel gets trapped inside it. This could also cause the same symptom as a plugged vent. The hose should be inclined so fuel always travels down and into the tank, it shouldn't be horizontal or dipping lower at any point.

[terry]

ITS STRANGE THAT YOUR ALARM WOULD GO OFF ON A FUEL PROBLEM.WHEN THE ALARM IS HEARD THE MOTOR GOES INTO RPM REDUCTION AND WILL NOT LET YOU GIVE THE MOTOR ANY POWER.THE BUZZER IS USUALLY  HEARD ON A OVERHEAT/OIL DELIVERY PROBLEM.

[Eric_Michael]

ITS STRANGE THAT YOUR ALARM WOULD GO OFF ON A FUEL PROBLEM.WHEN THE ALARM IS HEARD THE MOTOR GOES INTO RPM REDUCTION AND WILL NOT LET YOU GIVE THE MOTOR ANY POWER.THE BUZZER IS USUALLY  HEARD ON A OVERHEAT/OIL DELIVERY PROBLEM.

Yeah, even an idiot light is more useful than beep codes!

I did some digging around the Internet.  I found this site: http://www.maxrules.com/VROwarnings.html which lists a "steady constant beep" for a fuel restriction for V6 motors.  That matches the behavior I had when I had a plugged vent line. 

Another thing to check is your vent hose. Check to see if it is hanging anywhere in the boat in such a way that fuel gets trapped inside it. This could also cause the same symptom as a plugged vent. The hose should be inclined so fuel always travels down and into the tank, it shouldn't be horizontal or dipping lower at any point.

Pretty sure that is not the case.  I get a significant overflow when filling the tank and the gas station pump shuts off.  I am trained to hold paper towels over the vent and then wait for it all to flow through.  It usually soaks up a few towels.

The time I left the tape on the vent I had to run about 10 miles before I noticed the symptoms.  Taking the tape off resulted in a good intake of air being sucked into the tank.  Yesterday's problem happened within a mile of the launch.  I couldn't have drawn down the tank that far and created a vacuum in that short of time.

[Rich_V174SS]

Some of those engines do have a vacuum switch which will set off an alarm if there's too much vacuum trying to draw up fuel. I had a problem with a customer's boat once where there was so much debris in the fuel tank that the water separating fuel filter was clogging up every 10 minutes and choking off fuel flow killing the engine and the vacuum switch triggered the alarm each time. The engine was a 225 V6 with VRO and (believe it or not) the fuel pump was not the cause.

[Eric_Michael]

I got a hold of the guy who originally worked on this boat many years ago.  Long time family business out of Tacoma.  He remembered my uncle and remembered this boat. 

He suggested the problem is possibly sensor related or water pump related.  This motor will reduce its RPMs if it is overheating.  So if the water pump is not cooling or the sensor thinks it is overheating....well that could cause it to cut out as part of a self preservation safety measure.

Anyway, I will take the boat up to him on Saturday.  We'll see what he determines.  It would be nice if this was an in & out fix, but I suspect I will be short a boat for a week or so.

I'll update everyone with the results...when I know them.

Thanks,
-Eric

[terry]

YES PLEASE LET US KNOW AS IM HAVEING THE SAME PROBLEM.I PUT NEW THERMOSTATS IN MINE AND WAITING TO TAKE IT TO THE LAKE.MY MECHANIC SAID RUN IT IN THE LAKE IN STED OF MUFFS BECAUSE THE WATER IS COLDER OUT OF THE HOUSE.IF THAT DIDNT FIX IT WATER PUMP IS NEXT.

[Eric_Michael]

Status update....

Took the boat up to Tacoma today.  Stashed it at the previous owner's house rather than the boat guy's shop (friend of the family).  He will drop it off when the parts come in.  I feel better storing it there rather than at the shop.  (Yeah, paranoid Glastron owner...)

Talking to the boat guy...  He will order a new VRO pump and install.  He will check out the carbs while it is apart in case the fuel pump has been throwing crap into the fuel.  He will also install a real fuel filter to supplement the little one built into the motor.  Finally he will check the fuel tank pick up, just in case that is cracked and letting air into the line.

Hopefully it will be done on Thursday.  I will make a banzai run up to Tacoma after work to get it.  I will keep y'all posted...

-Eric

[Eric_Michael]

Well dang, that wasn't it!   

I had the VRO pump replaced last week.  We took apart the old pump as there were no obvious signs it was defective.  We did find some dirt inside the fuel section.  The diaphragm also seems a bit off.  As the mechanic put it, the diaphragm felt thin and more flexible than a new one.

The mechanic did recommend installing a fuel filter.  The motor has a small built-in filter, but he recommended a larger external fuel filter & water separator.  I did the mounting of the filter over the weekend.  It sits on the starboard side in the back of the gunwale.  I reinforced the plywood just to make sure I had a good mounting surface.  A few fittings from the hardware store and it plumbed right into the copper fuel line.





Last night was a warm evening, and being a Monday there was no one on the water - a perfect time to test!  Unfortunately I had the same problem as before.  It gets up to speed and then starts to cut out.

I tried to record a video of how it runs.  I mounted the mini camera tri-pod to the ski pole.  Note to self: Image Stabilization doesn't really stabilize (but it does cause a cool effect), and the internal mic sucks.  The motor really does not sound as crappy as the mic makes it sound!!!  At about 59 seconds in, you can hear me rev it in neutral and it hits the rev limiter. 

View this lousy video at your own risk:
http://www.youtube.com/watch?v=WKtdaS7kpKA

I got the boat home and attempted to duplicate the problem.  I warmed it up, and then reduced the amount of water flowing through the hose.  I did not shut the water off, I just took it from a 20ft spray to a 3ft spray.  This warmed the motor up a bit more.  I kept my hand on the head to make sure it did not get too hot.  Unscientific method: About as hot as a bowl of soup - hot enough to carry, but you don't want to hold on for a long time. 

I then shut the motor off and let it heat soak for a few minutes.  I turned the water on full and restarted the motor.  Sure enough, it appeared to hit a rev limiter at around 2500RPM.

Then I shut the motor off and removed the sprayer out of the back of the motor.  This is threaded with a garden hose fitting.  I hooked up my hose and reverse flushed the motor.  I got it good and cold - the evening dew was starting to condense on the heads.  Moved the hose back to the clamps and restarted the motor.  Ran great and did NOT hit a rev limiter.  Even as I warmed it up to operating temperature it did not try to throttle back.

Supposition:
1) The motor is not cooling properly.  It is time to replace the water pump.  Over temp causes limp home mode & rev limits the engine.
2) The motor thinks it is not cooling properly.  Over temp alarm causes limp home mode.

I believe the motor is cooling properly.  It pees water out the back a good 15-20 feet.  It is the same amount of discharge it has always had.  I would think if the water pump had gone south that I would have reduced discharge, and that is not the case.

I am going to go with the second possibility at this time.  I ordered port & starboard temp sensors.  They will be in tomorrow.  Hopefully I can test later in the week.  Wish me luck!

-Eric

[Rich_V174SS]

How about replacing the thermostats on the engine? I've seen them get all crudded up and cause temperature swings.

[Eric_Michael]

How about replacing the thermostats on the engine? I've seen them get all crudded up and cause temperature swings.

For some reason I thought this motor did not have a thermostat.  I could be (and probably am) incorrect on that assumption.  Good point, I'll need to dig into this deeper.

[Rich_V174SS]

If your engine is a V6 then there are two of them, one at the top of each cylinder head.

[wiliermdb]

0435597 should be the current part number for your thermos and the run about $25 - $30 each and you need two. They are located behind a screw-in plug at the top of each head. Very easy to get to.

[Eric_Michael]

Problem solved!!!!!   

I purchased new OEM temperature sensors.  A single wire for the port side and a double wire for the starboard side.  Real easy to install, simply take the plastic covers off and pull out the rubber plugs.  Not cheap though....  $115 for the pair.  Ouch.

After reading the posts about the thermostats I was thinking that was probably the issue.  I had run on salt the last time it was out and working, and did not get a good flush on the motor (low water pressure on the garden hose).  I thought maybe I had gummed up the thermostats, so when I launched the boat I was a little pessimistic.

I idled out of the marina.  Suddenly the RPMs dropped.  Uh-oh.  This was not normal.  Then my brain kicked in gear and I thought it through.  This boat has always been a PITA at port speed to dock.  It simply comes in too fast.  I had read up on the two wire sensor.  One wire is 'overheat', the other wire is 'up to operating temperature'.  This sensor had been going bad for a while as it had not been reporting the engine as 'warmed up'.  That was why it always idled fast!

Got out of the marina, got up on a plane, and glided past the area I had done troubleshooting the previous two times out.  As my grin started to spread, I rolled into the throttle.  No problem, it spun up to 5k RPM and flew right along!!!

There was no one else out on the water, but the wind did put a bit of a chop up.  We ran into the wind going up river for a few miles.  Coming back down river we set a new personal top speed.  We upped it by 1.2 MPH.  Because the VRO fuel/oil pump was recently replaced I have been running extra oil in the gas tank.  In case the new oil pump goes bad, I won't lose the motor.  When I go back to a 50:1 mixture, maybe it will even run better!

Interesting...  This is the same stretch of water we ran 62.6 on two years ago.  I came close on other water a bunch of times, but never topped it.



Thanks for everyone's help & advice.  It is good to have a group of enthusiasts to share my story with.

-Eric

[MarkS]

SWEET!  Glad you got her straightened out Eric.