Just Shoot Me

[Bud Kennedy]

For the past couple of years, I have been in a running gun battle with the motor gremlins.  A significant amount of money has been spent on this battle that resulted in the replacement of many parts on my 1991 Johnson Fast Strike 150.

Over the years the following items were replaced trying to identify and repair the problem.

Complete new fuel system from the tank to the motor.  This included all new gas lines and all new connectors. Six carbs were all serviced and cleaned and the jets replaced to factory specification.  A new fuel/water separator was installed. Also being replaced were the spark plugs and a new encoder and optical sensor were replaced.  At the same time the fuel line had a replacement of the primer bulb.

Recently, I replaced all the coils and also replaced the thermostats.  None of these things have cured the problem that is being experienced.

Here is a description of my overall issue.  The motor at all times has started easily.  Idle has always been good although from time to time a misfire could be detected.  After the boat has been unused for a few days the ugliest problem still remains.  After a smooth start and an idle out of the no wake zone I attempt to throttle up to go on plane.  At this time the motor bogs down almost like it is being fuel starved or flooding out.  Kind of like running on full choke if you know what I mean.  I can move to full throttle but the motor bogs down and can only reach about 2000 rpms.  This condition might last for several minutes and sometimes up to 15 minutes.  Then all of a sudden like a switch has been flipped, the rpms jump up to normal and off we go.  For the remainder of the day the motor runs and performs like a new one.  Absolutely no problems with starting or jumping to plane.

OK so now I have this first start of the day problem but only at the first jump to plane.  I am running short on ideas about what to do next. The power pack is old but not ancient but I don't know if a problem like this can come from a power pack.  There also is the reality that I could still have a carb problem.  I just don't know what would be most likely.  The fact remains that it seems that no shop that I have tried in the past has the ability to identify and fix this problem.   I feel like the only decision to make is to keep guessing and maybe I can stumble onto the problem.  I am running out of ideas and certainly running low on money to keep going.  I don't want to buy a new motor even if I could find one.

I guess what I am looking for are some additional ideas from the group that might give me some trouble shooting ideas.   Should I change the power pack? Or should I try to find a technician that works on carbs?  What do you think are my next logical steps to make.

[Princeton_Man]

Carbs and heat both came to mind, actually the intake manifold. I'd probably try re-torquing the intake manifold and carbs.

How long do you let it warm up before you take off? What if you let her idle for say 15-20, maybe even 30 minutes before pulling away from the dock? Will it make a difference.

[Mike Cork]

I'd be curious if squeezing the fuel bulb while experiencing the problem, floods the motor further or helps it? Of course this would take the nimble skills of a young man to pull off but it could lend a lot of input towards troubleshooting.

On a different note many, many years ago I had a similar problem that we chased for months. Issue was only at start up, after the motor warmed, no issues. I had a cracked block, the crack was so small and in the exact perfect place that when the motor warmed it basically sealed it's self for the day.

[Princeton_Man]

On a different note many, many years ago I had a similar problem that we chased for months. Issue was only at start up, after the motor warmed, no issues. I had a cracked block, the crack was so small and in the exact perfect place that when the motor warmed it basically sealed it's self for the day.

That's where I was going with letting it idle 20-30 minutes.

[Bud Kennedy]

Carbs and heat both came to mind, actually the intake manifold. I'd probably try re-torquing the intake manifold and carbs.

How long do you let it warm up before you take off? What if you let her idle for say 15-20, maybe even 30 minutes before pulling away from the dock? Will it make a difference.

Typical idle time is 15 minutes then another 5 minutes to idle out of the no wake.

[Bud Kennedy]

I'd be curious if squeezing the fuel bulb while experiencing the problem, floods the motor further or helps it? Of course this would take the nimble skills of a young man to pull off but it could lend a lot of input towards troubleshooting.

On a different note many, many years ago I had a similar problem that we chased for months. Issue was only at start up, after the motor warmed, no issues. I had a cracked block, the crack was so small and in the exact perfect place that when the motor warmed it basically sealed it's self for the day.

I have actually squeezed the bulb while this was going on but did not make a difference.  You are right you need to be a bit nimble to pull it off.

Cracked Block, Oh Heck NO , I don't even want to think about that one.  Go wash your mouth out please.

[Princeton_Man]

I'd be curious if squeezing the fuel bulb while experiencing the problem, floods the motor further or helps it? Of course this would take the nimble skills of a young man to pull off but it could lend a lot of input towards troubleshooting.

On a different note many, many years ago I had a similar problem that we chased for months. Issue was only at start up, after the motor warmed, no issues. I had a cracked block, the crack was so small and in the exact perfect place that when the motor warmed it basically sealed it's self for the day.

I have actually squeezed the bulb while this was going on but did not make a difference.  You are right you need to be a bit nimble to pull it off.

Cracked Block, Oh Heck NO , I don't even want to think about that one.  Go wash your mouth out please.

There could also be a leak at your intake manifold. Expansion from heat could be helping to seal it along with the vacuum. This is why I suggest re-torquing the manifold and carbs. It could be that easy. You can probably borrow a small torque wrench if you don't have one.

[Bud Kennedy]

Jim here is another thing that I found.  Looking at the port side of the motor, I noticed a small diameter hose of some sort lying near the bottom of the motor.  I can't see where it comes from or if it is supposed to be connected to something.  Will have to get an inspection mirror of some sort to see what I can see.  It is within reach of the bottom carb but don't know if it is supposed to connect there.  It is almost like some form of vacuum hose and there is no evidence of fluids that I can see.  Wonder what that might be.

[D.W. Verts]

Hmmm. Try hitting the choke while throttling up. See what that does. If the motor cleans out then you'll know.

That hose? Probably a crankcase ventilation line would  be my guess. It's been a LONG time since I worked on a Johnrude (or any motor for that matter).

It's just a fact that those old crossflow motors had some catankerisms (yes, that's a word- it's MY word). But keep good gas and oil in them and they lasted. As long as the VRO system was upgraded often or simply killed off.

Dale

[Pacific NW Ron]

Hmmm. Try hitting the choke while throttling up. See what that does. If the motor cleans out then you'll know.

That hose? Probably a crankcase ventilation line would  be my guess. It's been a LONG time since I worked on a Johnrude (or any motor for that matter).

It's just a fact that those old crossflow motors had some catankerisms (yes, that's a word- it's MY word). But keep good gas and oil in them and they lasted. As long as the VRO system was upgraded often or simply killed off.

Dale

A long time ago I had a 75 Johnson that did that same thing.  If you haven't already try what D. W. suggested.  Sorry to say I don't remember what I did to fix it but I remember that for a while hitting the choke for a few seconds became part of throttling up. 

[Bud Kennedy]

Dale, If I operate the choke during take off there are no changes that take place.

[D.W. Verts]

Well, darn it. So much for the Hickbilly genius... Check that vacuum line tho'. It should reach a port on the crankcase, and they CAN cause some issues.

How about this- does your motor ever "sneeze", especially just after you've started it, while it's idling cold, or when you try to give it throttle cold? I'm asking for a friend.

Dale

[Bud Kennedy]

No sneezing.  The motor sounds very rock solid.  If it is a bit cold there can be a misfire but only at no wake speed and it feels like just a single cylinder.  It does not misfire at running speed.  All in all the motor sounds really good up until it won't produce rpms on first jump to plane.  It can struggle for up to 15 minutes then all of a sudden like flipping a switch it takes off and runs and performs normal the rest of the day.

[D.W. Verts]

The sneeze would be a bent reed, which can sometimes sort itself out after a motor warms up. I'd bet on a carb issue if that vacuum line doesn't pan out. Most electrical issues get WORSE after a motor reaches operating temps, in my experience. Sorry Bud- I did this forever, but I haven't done it in, well, forever.

The carb thing COULD be a sync issue, but would more like be one has a float sticking, or you have a -hi speed circuit issue.

One more thing- any fuel smells on the cold engine at idle? I think you would have mentioned that. Have you pulled the cowl off before you start the engine cold? Sometimes it helps to "feel", "hear", and SMELL that engine after it first starts. You might try that next time. Plus, if an engine runs better without a cowl, then there's a rare but possible problem in itself.

Dale

[Bud Kennedy]

Dale I can detect a faint fuel smell but nothing very significant.  I agree with you on the carb deal even though I am gonna replace the power pack and new spark plug wires while I am at it.  I have gone this far so might as well keep going.

[D.W. Verts]

If just one float is out of adjustment or sticking some (hence the gas smell) that's all it would take for you to have the exact issues you're talking about. Of course, those older 2-strokes ALWAYS had some gas smell.

Plug wires and a power pack just make sense. The thing about electronic components- you replace something (power pack) and the next weakest link (stator) takes over. Good luck with this sir. You have a beautiful rig (just think how it would look with a brand-new 4S on it)

Dale

[Bud Kennedy]

here are a couple of pics of the infamous hose to no where. 



This hose was just laying in the bottom of the motor not connected to anything




This is the other end of the hose connected to the balancing tube

[Bud Kennedy]

The next Bullet in my Gremlin hunting arsenal



I hope this helps.

[Bud Kennedy]

Today was installation day for the new power pack.  Got everything all put back together and tested on muffs in the driveway.  The for real test will be tomorrow on the river and that should tell me how I did for sure.  The only problem I had was I had pulled the fuel filter to just check it out and did not get it put back in like it should and this resulted in a fuel leak.  Re set every thing and tested and that took care of the leak.   The motor started as it should but seems a bit rough but that is hard to tell on muffs in the driveway.  Rev was good and the idle seemed rough but certainly not bad.  Total time to perform this work was just over 2 hours.  I am looking forward to getting it on the river tomorrow.  We are having some misty rain in the area today so I put the cover on the boat and will do it tomorrow.

[D.W. Verts]

An engine will not idle on a hose like it will in the water. good luck with it.

Oh yeah- prayers sent for your stator...

Dale

[Bud Kennedy]

On water test today was perfect.  No problems at all.  Motor was smooth and powerful and jumped on plane quickly with no bogging or misfires of any type.  I don't know if it is fixed but it sure ran well today.  Going back out tomorrow for some fishing and we will see how it does at that time.  So far so good.  Keeping my fingers crossed thats for sure.

[Wizard]

Well, thank goodness.  I had just cleaned my .45 when I saw this topic. It sounded like your motor had put you in real pain. I was ready to help out, Bud.  Could be that your topic misrepresented the thoughts in your post.

Wizard