3.0 tech needed

[timrod]

91 3.0 with points dist !!! Engine only has 50+ hrs sense over hauled with every thing, bored and pistons new head new cam and every thing else i could put .This thing will run perfect for 20 to 30 miles @ 3000 rpm till we get there .I can throttle down slowly to idle speed and it will start to cut out just a little on idle and then stop !!! It will not crank for 10 to 15 mins and will start back and run perfect for a short period till it idles again .If you can get started and get it in gear running and above idle it will run perfect, if you dont let rpms down low if you do it will die and you will have to wait !!!! Ok now i will tell you what i have done!! New Manifold and riser ,new dist, new coil ,replaced resistor wire in harness ,then changed to regular wire and went with a built in resistor.New wires new plugs ,timing is set to book specs .When it does this i can take off plug wire at a plug and it has a blue spark at least a inch ,take off flame arrestor and pump gas and it has two streams from accelerator pump .That is gas and air and spark .So tell me is this dam thing vapor locking in the intake when it is getting hot ???? Oh and i forgot the water temp is 160 degree and cool enough i can take the cap off with no pressure !!
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[bigdan1]

Re: 3.0 tech needed

I`d suspect more a defective condenser ....( cheap $3.00 part)

when really hot it shorts then when cooled down it returns to normal

 

[timrod]

Re: 3.0 tech needed

Its brand new ,and the other prestolite dist points and condensor was new also.And it is has blue 1 inch spark at the time it does this mess .Every thing is new and new again two coils and two different dist even as i posted before new resitor wire ,and then went with a copper wire and changed the coil to built in resitor .I have tryed it all . Thanks for the reply

 

[Howard Sterndrive]

Re: 3.0 tech needed

did you ever compression test it when it's hot and acting up?
How is it for power when it runs it's best?

 

[Don S]

Re: 3.0 tech needed

Read this thread and do the tests.
http://forums.iboats.com/showthread.php?t=283269

I would bet money you will find a high vacuum situation that slowly builts up but will still pull fuel at higher speeds, but not at idle.

 

[fossill]

Re: 3.0 tech needed

Its brand new ,and the other prestolite dist points and condensor was new also.And it is has blue 1 inch spark at the time it does this mess .Every thing is new and new again two coils and two different dist even as i posted before new resitor wire ,and then went with a copper wire and changed the coil to built in resitor .I have tryed it all . Thanks for the reply

Don't mean anything. I've replaced lots of points and condensor only to not have the engine run properly or start. One particular brand was really bad for this. I always try to avoid "jobber" parts and stick with oem.

 

[timrod]

Re: 3.0 tech needed

did you ever compression test it when it's hot and acting up?
How is it for power when it runs it's best?

No no more hours on engine than it has after i built it was no need to ck that . The power is good for a 3.0 boat will run 38 on gps and 4200 rpm .

 

[timrod]

Re: 3.0 tech needed

Don't mean anything. I've replaced lots of points and condensor only to not have the engine run properly or start. One particular brand was really bad for this. I always try to avoid "jobber" parts and stick with oem.

I ruled this out when i did a different dist ,it was tried with and old set and then the new .I think between 2 dist and 4 points and condenser i coverd that ,but any thing is possible .

 

[timrod]

Re: 3.0 tech needed

Read this thread and do the tests.
http://forums.iboats.com/showthread.php?t=283269

I would bet money you will find a high vacuum situation that slowly builts up but will still pull fuel at higher speeds, but not at idle.

I adjusted the carb with a vacum gauge but have not cked it when it did it .I will ck that but what will do that ?

 

[Simoniz]

Re: 3.0 tech needed

Is the fuel tank filler cap failing to vent?

 

[Don S]

Re: 3.0 tech needed

I adjusted the carb with a vacum gauge but have not cked it when it did it .I will ck that but what will do that ?

READ the link I posted. It has nothing to do with the vacuum on the carb, it's for testing the fuel tank vacuum while running.

 

[chomamma]

Re: 3.0 tech needed

Could be a fuel supply issue at idle. Do you have 5-7 lbs fuel pressure at idle. Filters clear and check ball free?

 

[timrod]

Re: 3.0 tech needed

I have restored this boat from the inside of hull to seals on the windows .I have restored the fuel tank and replaced every hose and fuel filter base and all clamps .This fuel tank has been lined with por15 and is clean and it has nothing stopped up or cloged or the vent it is new and the hose is new I will do the vacuum test on the fuel line .I just don't know how that is gonna tell me ,when the thing is getting gas when it it does this .I took the top off of the carb and the bowl was a 1/4 to a 1/2 from the top and it would squirt two streams every time you open the throttle .