1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

[tacconelli6]

The I/O has just been rebuilt. Been sitting awhile. Ran good for three weeks. Now has trouble engaging at low idle.
I went through the electrical. I broke carb down and soaked and cleaned(Holley two Barrell 300 cfm). Replaced fuel filters. Took out and ran at different speeds and adjusted High/Low idle pilot screws(to the best of my ability).
I got it idleing @ 600-650 rpms. and from neutral position when I engage she won't stay going w/o a little throttle play. I raised idle to 750-800 and get better response, but still not consistently running when I engage.

I can play w/ it and get it engaged in Forward and then it will low idle in gear and operate OK. I just know that I shouldn't have to do that.

It fires right up in the driveway and idles just fine, but, under load(in the water) it just don't got! I wonder due to the age of the engine if a lead additive would help, as I know this engine was not made to run on modern fuel. Thanks in advance for all help.

 

[NW Redneck]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

Welcome to iBoats! Another white anchor to swell the ranks! I have the same drive/motor setup in my boat ('75-76). Idle should be 500-600 according to my manual. Mine is around 575-600 and shifts and idles nice and smooth. I resurected mine after sitting for 12+ yrs and was dry siezed when I got it. I got the motor freed up and got a rebuild kit for the carb and did it myself. I just followed the instructions to the letter and had no troubles. And I've been running regular mid-grade unleaded for the last 3 yrs. Have you gone through the entire fuel system from tank to carb? Maybe missed a filter somewhere? Crud in the tank? If all that is OK I'd check your fuel pump pressure. Good luck!

 

[tacconelli6]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

No, I didn't take all fuel lines off, I need to and probably replace them as they are old and the ethanol will probably begin to eat at them. Thanks for your help. I had a feeling that the motor should be able to engage at idle lower than 700.

just got into this thing and... I need a manual:redface:.

 

[supercab78]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

Are you saying it won't engage into foward, or that it stalls when you engage into any gear? I've been running unleaded for 20 years in my 1975 omc, with 650 hours, no problems. When you say you went through electrical do you mean the points, setting dwell and timing?

 

[NW Redneck]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

No, I didn't take all fuel lines off, I need to and probably replace them as they are old and the ethanol will probably begin to eat at them. Thanks for your help. I had a feeling that the motor should be able to engage at idle lower than 700.

just got into this thing and... I need a manual:redface:.

This may well be the problem. If you are just starting to use ethanol-mix gas, it could be loosening up any contaminants in the tank, lines, etc. Your initial post said it ran fine for a few weeks before the problems started, which seems to support the theory. Try changing your filters again and see what happens. You may have to change then a few times before all the gunk is worked out of the system.

And yes, you need a manual.

Let us know how you make out. We like to have closure around here.

 

[tacconelli6]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

Are you saying it won't engage into foward, or that it stalls when you engage into any gear? I've been running unleaded for 20 years in my 1975 omc, with 650 hours, no problems. When you say you went through electrical do you mean the points, setting dwell and timing?

-It engages and then stalls out in any gear, unless I play w/ the throttle and get lucky.

-Yes, set points opened them up a match book width
-Didn't set the timing and don't know what dwell is.

 

[tacconelli6]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

This may well be the problem. If you are just starting to use ethanol-mix gas, it could be loosening up any contaminants in the tank, lines, etc. Your initial post said it ran fine for a few weeks before the problems started, which seems to support the theory. Try changing your filters again and see what happens. You may have to change then a few times before all the gunk is worked out of the system.

And yes, you need a manual.

Let us know how you make out. We like to have closure around here.

changed filters and ran it for a couple hours and they are pretty dirty. I don't have the experience to denote how filthy they should look, I have a purlator in line w/ the glass holder and it had a bit of sediment and tarnish crap in it already. Probably should clean the tank.
Once I get her going and open it up I can them drop back to low idle cruise w/ no stall outs.

 

[a70eliminator]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

Matchbook points are only a last resort to get you going in a emergency, It would be a stroke of luck if your dwell is anywhere near 29-30.

 

[NW Redneck]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

changed filters and ran it for a couple hours and they are pretty dirty. I don't have the experience to denote how filthy they should look, I have a purlator in line w/ the glass holder and it had a bit of sediment and tarnish crap in it already. Probably should clean the tank.
Once I get her going and open it up I can them drop back to low idle cruise w/ no stall outs.

If you've got that much visible gunk in a couple of hours, you need to clean out your system. Either keep running it and keep swapping filters every few hours, or flush the tank and replace your hoses first. As well as a clean fuel system, you need to get your timing set right. Here's some info to get ya going:

 

[Uraijit]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

-It engages and then stalls out in any gear, unless I play w/ the throttle and get lucky.

-Yes, set points opened them up a match book width
-Didn't set the timing and don't know what dwell is.

Dwell is how long the points are in contact with eachother. Dwell is measured as an angle. So 31 degrees of dwell means that the points are closed for 31 degrees of distributor rotation. The easiest way to set it is with a "dwell meter" you can buy one at Harbor Freight for $30 http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=95670 Or I think you can just do the "free rental" thing at Autozone. I'm pretty sure they have dwell meters there...

If not, just buy the meter, or find someone who has one that you can borrow.

Set the dwell, then set the timing, then double check the dwell, then double check the timing.

It sounds like your problems are more fuel related, but you should get fuel and spark set up properly from the get-go.

 

[supercab78]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

If you do get around to setting dwell, on a ford you get it close with feeler gauge .017-.019 I think, then check with dwell meter. If you just snug down the screw, check dwell then tighten the screw your dwell will probably change. Which is why Uraijit said to check it again. But like he said it sounds like you have fuel issues to deal with first.

 

[chiefalen]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

Check fuel pump pressure should be 4-6 pounds. Run it on a external tank till you have it running right. That way you take the onboard tank out of the equation.

Maybe a carb rebuild.

Filters cleaned run the engine clean the filters. Hows compression?

Really want to know whats wrong do a vacuum check.

http://www.secondchancegarage.com/public/186.cfm

 

[tacconelli6]

Re: 1977 OMC se 300 sport w/ ford 302 175 hp. low speed idle problems

Thanks For all of this info. Men. I will udate soon.

 

[tacconelli6]

Am I doing this right?

Am I doing this right?

OK, I got the dwell meter and I have been attempting to set the dwell w/ no success.
This is what I am doing:
I get the points to the tip of the Bolt( don't know what to call the hexagon that the point strikes). This puts the points at the maximum distance apart.

I'm using a feeler gauge to adjust the distance and Then I run the motor and I touch the black lead to the neg. battery tirminal and the red to the neg. side of the coil or low voltage lead from the distributor.

I have had it from 17 to 27 degrees but cannot get it to 31.

It seems to run good at 17-21

I was trying to use the feeler to keep consistant adjustments. I started at .19 and have gone down to .13 and it isn't starting or running good down this small of a gap.

.18 - .17 seemed to run good, but the meter then read that it was at 22 degrees.

 

[NW Redneck]

Re: Am I doing this right?

Re: Am I doing this right?

You may have to do a little back and forth between idle speed, dwell and timing as changing one can affect the other. Start with getting your idle speed within range, then set the timing, then adjust the dwell. Once you get them as close as you can, re-check your idle speed, timing and dwell again. It may take a few timing-dwell-timing-dwell cycles to get it right. You must have patience young jedi.

 

[tacconelli6]

Vacuum Test

Vacuum Test

Yes, Goooose-fraa-baaaa...Gooooose-fraaa-baaaaa

Vacuum test indicates retarded ignition timimg.

so now that the sun is done beating on my head I shall attempt to set the timing.

I am starting to really fit well down in this engine compartment. I may just get a pillow and stay out in it tonight

PS. Beer tastes better in the shade!

 

[NW Redneck]

Re: Vacuum Test

Re: Vacuum Test

Just wait 'till you have to remove your tilt motor! That's allways a good test of ones patience and flexability!

 

[tacconelli6]

degree indicators

degree indicators

I can see the point off of the block, However, I don't see the degree indicators on the harmonic balancer. It is painted ford blue so...maybe they are under the paint?

 

[NW Redneck]

Re: degree indicators

Re: degree indicators

To quote a much respected board member.........

Ayuh.


Put a dab of white paint, chalk, etc on the mark when you find it. Shows up great with the timing light.



Edit: I just had a look at mine, and the stampings are fairly fine-lined so paint can easily obscure them. The paint on mine was chipped off over the markings, but intact on the rest when I got it. Looked like the previous owner had scratched it off.

 

[tacconelli6]

Re: Vacuum Test

Re: Vacuum Test

Just wait 'till you have to remove your tilt motor! That's allways a good test of ones patience and flexability!

Funny, That was the first thing I had to do when I bought it in order to replace the worm gear shaft. I just smiled and said "yup, worry free boating"
that makes all this a bit easier.

I will say though, I am learning alot about this boat and it makes me more confident for when I do get it out. We have some big deep lakes here in Coeur d' Alene area. We mostly go to lake Pond O'Reille (Pond-o-ray). which is 58,000 acres and 1,000 ft. deep in some spots.