boat will not crank without throttle advanced

[wpowell323]

I was wondering that the tps % should read on a 350 mpi when the throttle was not advanced? My boat started not cranking without having the throttle advanced just slightly. I hooked it to the ddt and with the throttle not advanced the TPS is at 0%. I adjusted the throttle cable where the tps reads .5-1.5% depending on where the arm exactly is and it cranks and idles right about 600 and seems to run fine. My question is do I have a bad TPS since it reads 0%? and it stays at 0% as you spin the motor, or should it read just a little to get the motor to run? The IAC seems to be opening and closing, It reads 0 with the key on but not running, but advances as soon as the motor beings to spin.

 

[Don S]

Re: boat will not crank without throttle advanced

That is not how you adjust a TPS, It should read 0% at idle. It's probably not even your problem.
The engine should idle with the throttle cable removed and the throttle plates completely closed.
You need to find out what the real problem is, not hide the problem.

What is the engines serial number, 350 mpi doesn't tell much.

 

[wpowell323]

Re: boat will not crank without throttle advanced

That is not how you adjust a TPS, It should read 0% at idle. It's probably not even your problem.
The engine should idle with the throttle cable removed and the throttle plates completely closed.
You need to find out what the real problem is, not hide the problem.

What is the engines serial number, 350 mpi doesn't tell much.

The serial number is OW389177

I did not adjust the cable enough to even open the throttle plate, just enough to move the arm and therefore advance the TPS, the arm has a little slop in it and therefore it maybe taking the TPS out of its proper range to function properly. Again that is why I am asking the question, if I wanted the problem "hidden" i would just leave it alone since it runs perfect now.

 

[alame]

Re: boat will not crank without throttle advanced

That is not how you adjust a TPS, It should read 0% at idle. It's probably not even your problem.
The engine should idle with the throttle cable removed and the throttle plates completely closed.
You need to find out what the real problem is, not hide the problem.

What is the engines serial number, 350 mpi doesn't tell much.

not wishing to stir the pot here but I don't see where the poster made any reference to ' hiding " the problem that was asked about.......you may not have forgotten too much about boats but you seem to have forgotten about being civil ?

 

[Bondo]

Re: boat will not crank without throttle advanced

I don't see where the poster made any reference to ' hiding " the problem that was asked about.......

Ayuh,... This is a micky mouse bandaid, Not a fix....

I adjusted the throttle cable where the tps reads

 

[wpowell323]

Re: boat will not crank without throttle advanced

Ayuh,... This is a micky mouse bandaid, Not a fix....

There again, I am here wonndering what I need to do to fix the problem, I made the adjustment to make my boat useable, if I wanted to keep it "patched" I wouldn't have asked for help. Not sure why people feel the need to chime in with no real help, but I thought I made it clear I am trying to fix the problem and am wondering what i need to look for.

 

[dubs283]

Re: boat will not crank without throttle advanced

you need to be more specific with what your problem is

you say the engine does not crank without some throttle advance, my first guess is the neutral safety switch

okay, then you say you have a ddt, great!! do you know how to properly use it??

now i'm thinking you have some improper terminoligy here, crank and start are two completely different things and the words should never be interchanged

crank and turn over, yes

so now you have an issue with the engine not starting?? it turns over/cranks fine??

have you looked at the fault codes with the ddt?? (you really should use a cds on this engine, but a ddt will work)

it sounds as though the IAC is not properly working, they are usually the culprit in this type of situation, check the faults and go from there

 

[wpowell323]

Re: boat will not crank without throttle advanced

It has no faults that show up in the DDT. I ran the auto test and everything comes back fine. With the boat in neutral with no throttle advance it will spin over but not start. If you advance the throttle to where the TPS reads even .1% the boat will start and seems to run perfect. If the TPS reads 0% it will not start. Maybe this will clear it up.

 

[dubs283]

Re: boat will not crank without throttle advanced

the IAC won't always show a fault if it isn't working properly

adjusting the throttle cable to get the engine to run is not the proper fix here

a cds may show a fault where the ddt does not but thats not guaranteed, unfortunately you dont have a cds to check. using a ddt on your engine is like an accountant using an abacus, it may get the job done but its a hassle

my WAG is the IAC is faulty, its not unusual to see them go out on the MPI engines. for every 20 IACs i replace, i replace maybe one TPS, can't remember the last time

 

[Don S]

Re: boat will not crank without throttle advanced

It has a problem, just not one that shows up as a fault code. Things like the IAC, or MAP, ECT to name a few, can fail witout setting any kind of code. Did you check the IAC per the manual? Not just for codes.