Hi,
First post on this awesome site. I am hoping for a bit of help as I am running out of ideas. I bought a $500 1978 Forumla Thunderbird F20 that has an OMC 240 (351w) with a Holley. It did not run and appears to not have in a few years, but the motor had been rebuilt. The paint is good and the freeze plugs look almost new. It was full of anti-freeze (San Juan fresh water cooling system).
I have been able to get it running by changing out the fuel, new spin on fuel filter, new plugs, points, rotor/cap, and rebuilt the carb (Holley 4160). It was dumping fuel into the intake and I discovered debris in the needle/seat that was keeping the float from completely stopping the fuel from entering the bowl. I fixed this.
No matter what I do, I cannot get it to idle below 1000rpm before it slowly starts sputtering and dies. Two things come to mind, this is the first carb I've ever rebuilt (Holley Renew kit) and also I timed it by ear.
So, I am going to use a timing light to set it at 10 degrees BTDC. Should have done that to begin with. I am also going to put the old power valve back into the Holley as I could not see the numbers and think the one in the kit may have been different. The kit was very generic and may not have been a marine kit after all (it's what Napa Auto sold me after I gave them the boat info and the numbers from the carb). Oh, and yesterday I put in an Ignitor II points eliminator kit, but the idle still does the same thing.
Am I missing anything here? Besides the idle and double checking my carb rebuild, any other ideas? One last thing, the intake appears to have some rust or corrosion inside that I saw when I removed the carb. Enough to concern me. Should I pull it and have it hot tanked to rule that out? I do see aftermarket intakes fairly cheap that could be another option.
When the motor is running, it has great oil pressure (50-60) and does not smoke from either the exhaust or the valve cover breather so that is a good thing.
Thanks and sorry for the long post..... Wait til I get the motor figured out and move on to the OMC 800 outdrive. That will generate many more questions. Btw, I am attempting not to put too much money into this five hundred dollar boat (yea, right) until I figure out if the motor/outdrive are going to work and do not have any major issues.
Thanks,
Chris
Washougal, Washington
First post on this awesome site. I am hoping for a bit of help as I am running out of ideas. I bought a $500 1978 Forumla Thunderbird F20 that has an OMC 240 (351w) with a Holley. It did not run and appears to not have in a few years, but the motor had been rebuilt. The paint is good and the freeze plugs look almost new. It was full of anti-freeze (San Juan fresh water cooling system).
I have been able to get it running by changing out the fuel, new spin on fuel filter, new plugs, points, rotor/cap, and rebuilt the carb (Holley 4160). It was dumping fuel into the intake and I discovered debris in the needle/seat that was keeping the float from completely stopping the fuel from entering the bowl. I fixed this.
No matter what I do, I cannot get it to idle below 1000rpm before it slowly starts sputtering and dies. Two things come to mind, this is the first carb I've ever rebuilt (Holley Renew kit) and also I timed it by ear.
So, I am going to use a timing light to set it at 10 degrees BTDC. Should have done that to begin with. I am also going to put the old power valve back into the Holley as I could not see the numbers and think the one in the kit may have been different. The kit was very generic and may not have been a marine kit after all (it's what Napa Auto sold me after I gave them the boat info and the numbers from the carb). Oh, and yesterday I put in an Ignitor II points eliminator kit, but the idle still does the same thing.
Am I missing anything here? Besides the idle and double checking my carb rebuild, any other ideas? One last thing, the intake appears to have some rust or corrosion inside that I saw when I removed the carb. Enough to concern me. Should I pull it and have it hot tanked to rule that out? I do see aftermarket intakes fairly cheap that could be another option.
When the motor is running, it has great oil pressure (50-60) and does not smoke from either the exhaust or the valve cover breather so that is a good thing.
Thanks and sorry for the long post..... Wait til I get the motor figured out and move on to the OMC 800 outdrive. That will generate many more questions. Btw, I am attempting not to put too much money into this five hundred dollar boat (yea, right) until I figure out if the motor/outdrive are going to work and do not have any major issues.
Thanks,
Chris
Washougal, Washington