Test Drive [motor bogging]

[dieselcat]

Got to take my new but used motor [1995 evinrude 88 SPL] out today for a test drive.Seemed to run fine at first,then it would act as if it was bogging.It would only hit 4000 rpm's,maybe 4100 at most.so i took off the hood to make sure it wasn't overheating,everything felt fine,nice and cool.shut the motor down for about 10 minutes,re-started it and took off again seemed to run better for a minute,hit about 4500 rpm's this time and sounded alot better but still not the 5500-6000 rpm's it's supposed to be getting.so just for grins i hit the choke button and bam right back to 4500-4600 rpm's but still not anywhere close to 5500-6000.

Everytime i would hold the choke button in it would run at the 4500 rpm,but as soon as i would let off the choke it would go back to the 4000 rpm and act as if it was bogging [starving for fuel] Just put brand new fuel line and bulb from tank to motor so i'm thinking i can rule out needing a fuel line or new bulb.

Also noticed that motor is not charging battery,started out with 12.5v and ended up with somewhere around 11.6 or so after running fishfinder and starting motor several times.

Any info on where to start would be greatly appreciated!

Also if this help any the boat is a landau pro 17 and the motor has a 13.25X19 p

Thanks,
Mike.

 

[greg carr]

Re: Test Drive

Re: Test Drive

have you checked the compression?

 

[dieselcat]

Re: Test Drive [motor bogging]

No i have not,am going to first chance i get tomorrow.

 

[5150abf]

Re: Test Drive [motor bogging]

Sounds like you found the problem to me, if you hit the choke and it ran better that tells me that it isn't getting enough gas.

That is a pretty classic symptom of dirty main jets, your motor has 3 sets of jets, idle, mid and high speed, it will run fine to a point then not gain anymore rpm because that is all the gas it is geting, like a partial throttle setting.

The jets you want are located behind the drain screw on the float bowls, pull the drain screw and you will need a long skinny screw driver to get them out, run a stranded copper wire through the jet, just pull back enough strands to have the wire just fit then run it in and out a couple times.

You can do this wihtout removing the carbs but I wouldn't reccomend it as you almost always contaminate them getting them back in, they may look clean but it doesn't take much to make that very small opening too small.

Do a compression check to, always good to know, hot preffered btu cold is okay, just do it the same everytime so your numbers a comparable.

 

[tashasdaddy]

Re: Test Drive [motor bogging]

agree with 5150abf, what is the prop on it. it may be propped for only 45-4600. i never attempt to do a carb on the motor. read this
http://forums.iboats.com/showthread.php?t=244013

 

[dieselcat]

Re: Test Drive [motor bogging]

The prop is a michigan wheel apollo 13.125 X 19.the boat had more than enough take off power. depending on what happens after the carb rebuild i doubt it would hurt to go with a 21p.

 

[splitshot]

Re: Test Drive [motor bogging]

does the boat have a tachometer on it ?? the reason i ask is my 140 quit charging and my tach started acting funny it was twitching back and forth...ended up being a rectifier

 

[dieselcat]

Re: Test Drive [motor bogging]

Yes i do have a tach,and i just replaced the rectifier about a week ago and my tach still didn't work after replacing it,so i hooked it up directly to the yellow/gey wire from the stator.

Had the impellar replaced at the shop cause motor was getting hot,tech said i might want to replace head gaskets also because they appeared to be leaking at some point.Bought new head gaskets yesterday and installed them,everything looked good inside the cylinders, walls nice and smooth.

When i took the plugs out after test drive they where all white,not sure what this means can someone help me out?Before test drive just running it at idol and a little above the plugs where always nice and black,with plenty of gas/oil on them still.

 

[tashasdaddy]

Re: Test Drive [motor bogging]

looking steam cleaned is water in cylinder, don't know white. start a thread and reference this one. "white spark plugs" as heading.

 

[splitshot]

Re: Test Drive [motor bogging]

sounds like its running lean

 

[Randybeall]

Re: Test Drive [motor bogging]

How many posts have started out, do you have a manual? The engine manual has a test procedure for the charging system. Since a diode did not kick off the charging system and the tach works with an input from the stator a good guess would be regulator. That is a guess, get the book do the tests before you buy parts. Boats cost enough with out buying extra unneeded parts.
Pull the carbs and do a thorough cleaning of them. Gummed up carbs likely cause a lot of boats to be sold for less than they are really worth because the orignal owner thought the engine was really failing.

 

[dieselcat]

Re: Test Drive [motor bogging]

Ok,just wanted to thank everyone for info.Thank,you!!

Rebuilt carbs today and put em back on. had to take hammer and screw driver to beat the fast idle thingy down cause i broke the darn handle off the other day when i was exiting the boat,it got cought on my shirt.
Started and ran fine.punch the throttle down and hold on cause it's sure runs alot better than before.
Runs strong throughout the whole rpm range,only thing is i am still only about 5000 rpm's,would hooking the tach directly to the yellow wire from stator cause it to read different?also my tach climbs real slow when motor is off,but when i turn key on it zero's like it's supposed to.If i remember right i have to tach set on 6P on the back,is this right?

 

[Mas]

Re: Test Drive [motor bogging]

I think you better get the "white plugs" figured out first...sounds like too lean...equals fried motor. What mix ratio are you running?

MAS

 

[dieselcat]

Re: Test Drive [motor bogging]

I am useing 50:1 mix.pulled the plugs today and they are still white,brand new champion QL77JC4's just put em in after the carb rebuild.Any way to test the fuel pump on this motor?

 

[crb478]

Re: Test Drive [motor bogging]

I am useing 50:1 mix.pulled the plugs today and they are still white,brand new champion QL77JC4's just put em in after the carb rebuild.Any way to test the fuel pump on this motor?

If you want to test the fuel pump have someone pump the bulb while you are running at WOT see if it picks up rpm. I doubt that the fuel pump is your problem, but I have been wrong before. If the plugs are white it indicates that the motor is running lean as has been mentioned before. Find out why. You can spray pre mix into the carbs to see if that helps. When were the carbs last cleaned?

 

[dieselcat]

Re: Test Drive [motor bogging]

If you want to test the fuel pump have someone pump the bulb while you are running at WOT see if it picks up rpm. I doubt that the fuel pump is your problem, but I have been wrong before. If the plugs are white it indicates that the motor is running lean as has been mentioned before. Find out why. You can spray pre mix into the carbs to see if that helps. When were the carbs last cleaned?

just rebuilt them yesterday

 

[dieselcat]

Re: Test Drive [motor bogging]

guess i spoke to soon.still not running right,better but not right.I've been reading in my manual going to do some testing over weekend and i'll let you all know the results.

 

[dieselcat]

Re: Test Drive [motor bogging]

pulled the inlet cover off the fuel pump and it doesn't have the O rings it's supposed to.someone put a homemade cork gasket on there that was covering the inlet hole atleast half way,will let you know how it goes

 

[dieselcat]

Re: Test Drive [motor bogging]

I replaced the O-ring on the fuel pump and it did help a little but not much.still not getting above 4600-4800 rpm,this thing is driving me nuts.i have taken the carbs off twice and ran wire through all holes and have taken out all orifases.just can't figure this thing out.someone told me that the previouse owner could of had the motor detuned,so it would run lower rpm's.Does anyone know anything about this?And is there any way i can check to see if it has been detuned?

 

[James R]

Re: Test Drive [motor bogging]

Checking the timing and doing the synchronization would be a good idea.
If the "detune" has been done then someone has been messing.
Use the manual and follow it step by step.
As for the "white plugs" do you mean clean and shiny or is there a hard white deposit on them.