new here engine just dies

[Jondsheeler]

Hi everyone.

I'm new here and the boat is new to me. I bought the boat in S.C. and brought it back to Georgia. The first weekend i got it and ran it. The motor started out running rough and then it got better as the day went on. I mostly had a problem with getting it started. As long as it was getting gas then it would start no problem but once I moved to put it into gear it would die. Then once it was moving going from forward to reverse it would stall. It's like it's starving for gas .Just a thought, the first time I ran it I used high test gas, thats all the station had. Also I'm using a red 12 gallon tank.

Now to today. With a freshly charged battery I went got gas did the 50/50 mix one pint to evey six gallons of gas. Used regular test gas. Got to the ramp and the engine started up right off the bat. Gave it a minute to warm up and it ran fine. Ran from nutral to forward and then to revrese with no problem. Ran this way for about an hour. Sounded and started just like a new motor. I thought it must have just been the high test gas that made it run bad two weeks ago. Then after an hour it started actting up again just like it did two weeks ago. Any one have any ideas as to why it would act like this.

I did check the bulb with it on and off the motor and it would get rock hard, but it did have a small leak under high psi. On the motor with it running the bulb would never get hard but I assume this is just becuase it was ruuning.

Any ideas as to what the problem is?

Finaly the boat is a 87, 170 with a 86 Johnson 90 rebuilt with only 15 hours on the rebuild.

Jon

[RickK]

Hi Jon, welcome aboard and to the 170 club.  
I realize that you bought it out of state but I think I would check with who you purchased it from and get the name of who rebuilt it.  With only 15 hrs on it, they should stand behind their rebuild and be able to help you figure it out.

[John Jones]

I did check the bulb with it on and off the motor and it would get rock hard, but it did have a small leak under high psi.

A leak in the bulb will allow air to be sucked in instead of fuel.  I'd change the bulb and if the lines show cracking I would change them too.  It's best to buy OEM bulb and lines.  The cheap generics will not last a year.  If there is no fuel filter I would install a Racor fuel filter/water separator between the tank and the bulb.



http://www.marinefilters.com/productdet ... W320RRAC01

[jdupree]

Jon,

I just had my Johnson re-built as well.  I thought I was having a fuel issue like yourself and mine turned out to be the power pack.  When a power pack starts to go it will display problems that appear to be a fuel issue.

If you engine is an '87, I would check your powerpack and compression.  Let us know.

[Jondsheeler]

I plan to check compression and then a few other things. The motor is a 86. Also It ideals at 400rpms. That seems low to me?

Jon

[RickK]

I still think there should still be some warranty time left on it, unless the "to the original owner" is applied  

[Jondsheeler]

I wished there was a warrenty. The place that sold it to me was very clear about that. That's partly why I got it at such a deal. If it had cost me any more to buy it then I would have not bought it from them. Though I must say that when you look at the enigine it looks brand new and it is one of the cleanest rebuilds I have ever seen. I'm replacing the bulb this week, some new spark plugs, fuel sep/filter, and I'm thinking of bumping up the ideal RPMS a little to see what that does.  If not oh well, I was planning on repowering it this winter with a Yamaha 115 or Etec 90 anyways. But if it starts running good then there would be no need to replace it.

Could the fact that it's a VRO have anything to do with it's problems I found a plcae were it use to have a line that feed it oil and now its gone and a piece of hose is there and its clamped off with a zip tie. Could it be sucking air in through that.

Jon

[RickK]

Give this sitea try.  Seemed to help a few of us in the past.

[Jondsheeler]

Hi guys  thanks for all the ideas. I have tried many and got some good results but still have problems.
 
It's hard to start. I have to raise the throtle to get it to start. Then when I get it started it runs fine sounds better then ever. I can then drop it to idel speed and it still runs fine. But as soon as I bump it into gear it stalls. Also the bulb will not harden up. I have tried two diffrent tanks with two diffrent bulbs niether holds firm. The gas just squirts right out the carbs then into the air intake. Also I noticed it will stall when I have it running and adjust the the tilt some.  
 
So far here is a list of stuff that has been done to the motor.
1. So far the motor has been completly rebuilt, or os I was told when I bought the boat.
2. I replaced all the hoses on the fuel system. They were all dry rotted, cracked, and held on by zip ties. Before this the bulb would stay firm. I guess I did something wrong when I put it all back together. Also before this I was abel to get it to run when I put it into gear but it was real ruff. Now it runs smooth just want hold as I put it into gear.
3. Replaced the spark plugs. tried to replace the wires but can not find wire that work for that motor.
4. Replaced the ractor water sep.
 
Any ideas? I'll check spark later today. But  
I beleave my problem is fuel system related.
 
Thanks in advance.
Jon

[JimCt]

Gas pouring out the intakes when you squeeze the primer bulb indicates one or all of your carburator float valves are leaking.  Leaking float valves will cause the engine to run rough since the carbs are delivering too much fuel.  Likely cause was bits of dried rubber from the old fuel lines broke free and got into the valves.

Only solution is to pull all the carbs and rebuild them, which is not a difficult job. You can get carb kits containing all the necessary new parts for the job. No special tools are required. While the carbs are apart you should clean them up inside and blow out the jets with compressed air.  When the carbs go back together they must be squeaky clean inside and out.  After the carbs are installed, you will have to readjust the idle jets per the book.  The way you have them adjusted now probably is way out of spec. to compensate for the float valve problem.

 The reason the engine stalls when you tilt the motor is that the angle of the float chamber changes with the change in the engine angle and the over-full float chamber spills a shot of gas out into the intake.  The effect is a momentary over-rich mixture which thus kills the engine.

[Jondsheeler]

When I changed the fuel lines I removed the carbs. Could I have bumped something or do I need to adjust something now? The carbs are actualy spotless. I was very careful but could I have rerouted the lines wrong. Is there a diagram of somewhere as to how they are suppose to be routed?
I'll pull them again but there seems to be something that I'm missing.

Jon

[JimCt]

The problem is inside the carburators.  The only cause for gas pouring out when you squeeze the primer bulb is debris in the float valve(s).  It's not an uncommon problem but the only solution is to pull them and rebuild them with new OEM kit parts.

If the lines were routed incorrectly the motor wouldn't have run at all.  From your discription of the engine operation, especially the stalling problem when you moved the tilt control points straight to the float valves.  Since the service history of the carbs is probably an unknown, a rebuild in any case would be a good thing to do.  My guess is that when the engine was rebuilt..and "rebuilt" could mean anything... the carbs weren't rebuilt.  If they were, a good mechanic would have replaced those cracked lines.

If you don't have one, you should pick up a service manual for your engine.  It will show the fuel line routing.  They are readily available at your local Johnson dealer.  With the book in hand you'll be able to adjust the carbs to factory spec.

[John Jones]

I think Jim has it.  If the bulb will not get hard and gas comes out the intakes, you have float/needle valve/valve seat problems.

[Jondsheeler]

I posted the same ? over at TMD and he told me to check and see if the throttle plates were clossing all the way. I also checked with the local marina and they said to rebuild the carbs. So sence it was much easyier and cheaper I started by checking the throttle plate. They looked closed but after I backed off the ajustment nut on the threaded rod and they closed maybe another 1/100". I then checked it by priming the bulb and the bulb got rock hard and held pressure and there was no more gas leaking from the carbs. I'll take it to the lake tomorrow and see how she runs.

Thanks for all the advice and the website guys. I'm not sure I have her fixed yet but I'm on my way.
Jon

[JimCt]

My money's still on those float valves.