Engine Failure During Hot and Humid Weather

[Makessense]

I'm very new at this.I have a 2000,21' CC Logic.For the most part I have been very happy with the boat and motor.The boat is powered by a 175 Johnson OB.During hot weather while fishing if I drift for fluke as the temp climb's above 85 it won't start or if I manage to get it started I have to hope I can get it beyond 800rpm's without stalling.Once I can get it to run it will do 35mph without a problem.While idleing to the ramp the same process repeat's itself.I've had it to three different Marina's and they can't figure out the problem.Anyone having the same problem.?Makessense.Fal5@peoplepc.com.Your help would be deeply apprecidated.

[Mike in Woodlands]

It sounds to me like an engine control module (computer) or some of the sensors which provide data to the computer.

It also sounds like a problem that will increase in frequency and severity. Check with a dealer who has good OMC experienced mechanic, as I suspect your Johnson is a '99 or 2000 model on your '00 boat.

Sorry I can't be any more help.
Mike

[Putershark]

Could also have low some quality fuel "boiling" in the fuel lines or your are getting a fuel vapor lock (starvation) condation.

Next time that happens, kill the smokes and take the fuel cap off to let it vent some. Then put it back on and see if it both starts and runs any better?

Keep us updated on this one

Thanks!
Dave

[Makessense]

Originally Posted by Putershark

Could also have low some quality fuel "boiling" in the fuel lines or your are getting a fuel vapor lock (starvation) condation.

Next time that happens, kill the smokes and take the fuel cap off to let it vent some. Then put it back on and see if it both starts and runs any better?

Keep us updated on this one

Thanks!
Dave

Thank you so much for your reponse.I have removed the fuel cap it did not make a difference.The last service proformed by the dealer was to replace the Vapor pump and O rings.Can you tell me more about the boiling in the fuel lines.Thank You.Makessense.

[Makessense]

Originally Posted by Mike in Woodlands

It sounds to me like an engine control module (computer) or some of the sensors which provide data to the computer.

It also sounds like a problem that will increase in frequency and severity. Check with a dealer who has good OMC experienced mechanic, as I suspect your Johnson is a '99 or 2000 model on your '00 boat.

Sorry I can't be any more help.
Mike

The motor is a 2000,and you are correct the problem has been getting worse year to year.However I've had to three different marine center's.The last one is where I purchased it.They had it for five week's part's problerm?I just returned the boat to them this week,same problem.Thank You for your input.Makessense.

[Putershark]

Low Octane / low boiling point fuels (meaning the actual level of the sample fuel) can start to boil in the fuel lines under extreme heat (mostly around the engine block area) and cause a "Vapor Lock" type of condition, thus starving the engine of fuel when under a load.

Now we have not seen much of this type of problem since the early to mid 80's and then the major cause was the reduction of lead in gas. I also saw that other posting about the alcohol blended fuels out west which can also cause such problems (due to the lower boiling point of fuels) and had a Coast Guard "flashback" when I fixed quite a few stranded boats over the radio that acted just like yours, by telling them to taking the fuel cap off to allow the system to vent some.

Now back then Mercury’s had the issue more than others due to being (not very logical) painted black of all colors. That color did not help the matter any and created a little reactor temp wise under the cowl of their engines and they really showed the problem in the summer months.

So I would also start looking for a vacuum leak of some kind around the different engine gaskets. Fire the engine up, let it idle (if possible) and try lightly spraying some “Throttle Body” cleaner around (be careful) the different mating surfaces (intake, injector /carb bases, etc.) and see if the engine starts to either increase in speed or stumble some from it “sniffing” the cleaner past the gaskets or a cracked vacuum line.

Trust me, it does not take much of a vacuum leak to cause major problem which usually only gets worse as the engine heats up and causes the gaskets or vacuum line to expand and take in air past the main air/fuel metering device, be it either the Throttle Body for injected engines or the base of the Carb.

You could very well have an electrical break down (ECU, Loose Ground wire, etc.) that can act the same way. Check all your ground connections and make sure your main start / running battery has at least 11.5 volts for anything under 10.5 VDC can cause a ECU to go “Brain Dead” and force the engine to run in what is called a “Limp In” mode.

Hope this helps ?

Dave

[sum1strange]

wow .... i jut bought a 2000 logic 210 cc this whole thing makes me kinda nervous. But my engine is almost new .... it's an obvious replacement ... it even smells new ..... but still i wonder if i should find a way to test this.

[Putershark]

Unless you are having the issue right now, I would not worry about such... Just make sure you take the time to run through a couple of "shake down" cruise's not far from shore at high speeds to make sure the newer engine is working as designed. Much easier to either get a tow when in the ICW or be able to run in at slow speeds when you are closer to the ramp than 20 miles offshore

Dave

[sum1strange]

I have had the boat for a year now and the the list of complaints is minor. I have read all of complaints from other logic owners here in this forum. As it turns out, this has been the best source of information i have found to resolve my issues. Anyway, here they are: 1) compartment drains 2) bilge fried just above the tank is now shorted ... but i am installing a new switch control panel and already installed fuse panel. 3) haven't install the "hull" drain. 4) barnicles: I haven't figured out how to get rid of the barnicles quite yet.

I have had "ZERO" problems with the engine.

[Fishahn]

sum1strange,
we all had the same little glitches you mentioned. all easy fixes. check out the site on comparment drains, I did this first year I had my boat. If you can't find info, I'll try to remember where I boat my thru hull drains. they are screw in types and work perfectly! hulll drain I did, but not sure it was necessary. I also fried my bilge once (stupid operator error), just changed it out and installed a new one, cut the lines and respliced right near the pump!

any questions fire me an email, my other address is tnc@together.net

fishahn (Rich Marron)