What next? STILL not running right?

I have been working on trying to get my 64 Interceptor (Ford 170ci) running right and am running out of options. The motor starts and runs great at idle. It will rev up to redline with NO load. When I try to get the boat to plane, it pretty much falls flat on its face, around 2200rpm....like its running out of fuel. After the engine is warm, all you have to do is "bump" the key and it fires right off.

To bring you up to speed.... I rebuilt a "modern", 1978 head from a 200 six banger earlier this spring. The head was mildly ported and milled .060, to bring it back to the specs of original 170 head. Doing this I'm running around 8.5:1 compression.the heads are CC'ing around 50 1/2...the original head had 52cc chambers. I also had to make a new "adapter elbow" to mount the Carter YH sidedraft carb. This adapter has a 1 3/4" I.S. dia. (this matches the new head's carb bore size) The original El was only 1 3/8" at the intake.

To date heres some of what I've tried..

Rebuilt Carb.
Rebuilt mechanical fuel pump.
All new fuel lines.
Added spin on type fuel filter.
Replaced Mallory dizzy from another motor.
New points, cap, condenser, rotor.
Changed ignition coil (from another motor)
New steel exhaust pipes.

Motor idles with around 18" of vacuum.
Set timing at 10BTDC per manual(as well as 10 to 15 more/less each way)
Dont know total advance, but with light it moves when throttle is cracked. (Looking for someone with an old Sun machine to spin it up).

Tonight I ran an electric fuel pump "plumbed" into a 5 gal gas can
and running directly to the carb, completely eliminating the boats fuel system ...still no go.

Per Boat Dr, I am ready to check cam timing... I am also going to change prop from a 12-13 back to a stock 12-12. Any other ideas what to try next?

FWIW...here'sa pic of the motor with the new SS carb adapter elbow...

Steve,
Billy and I have discussed the problem and he brought up the cam timing but that was before you had gotten the vac reading. I don't feel you'd be getting 18" with the cam off even by 1 tooth. However, you've done everything else!! Might as well take a look at it!!

Have you ever run it with the 12 pitch prop? If so, what did you get out of it for WOT RPM then?

Steve, before dinking with the cam timing, I sure as heck would be verifying that youre getting all of the mechanical advance out of the dizzy that you should. A decent timing light with a dial would make this very easy.

When Mark and I were out with Steve on GL, we did play with the distributor as well as the carb. Manually advancing the distributor did not increase the WOT RPM.

I'm leaning toward a carb problem or a vacuum leak (too lean in the midrange). It sounds to me like the enrichment circuit of the carb may not be working right.

You don't need a Sun machine to check the timing. Put a timing light on and see how far the mark is moving when you rev the engine. You can always calculate how far 20 degrees or so is from the zero mark and make another mark with a sharpie for reference. A dial back timing light is a necessity!

That engine looks so sweet I went back for another look! Also, I saw something that can cause your problem. There is an open hole in the intake below the carb!!! Put a plug in it and retry!!! If this is the problem you owe me a beer!

Brktracer wrote: I'm leaning toward a carb problem or a vacuum leak (too lean in the midrange). It sounds to me like the enrichment circuit of the carb may not be working right. You don't need a Sun machine to check the timing. Put a timing light on and see how far the mark is moving when you rev the engine. You can always calculate how far 20 degrees or so is from the zero mark and make another mark with a sharpie for reference. That engine looks so sweet I went back for another look! Also, I saw something that can cause your problem. There is an open hole in the intake below the carb!!! Put a plug in it and retry!!! If this is the problem you owe me a beer! No Beer... that is a pic of the motor while I was still working on it. The hole is plugged, well actaully the flame arrester's gas overflow is plumbed into it via a 1/8" copper line. The timing does advance when reved in neutral.. probably a couple of inches on the flywheel...just cant say exactly how many degrees. The carb I just put on it is a NOS marine one with updated accelerator pump etc. ($$$$

) BTW, I had tried two other carbs before breaking the bank for this one.

Make sure you aren't running fuel with ethanol in it. Most gas stations have 10% now and that was a big problem on all of my carburated engines. I know this is about as basic as you can get but it seems like you have done everything but buy a completely new crate engine...New plugs and wires are a good idea too, I didnt see any mention of that.

Toigs325 wrote: Make sure you aren't running fuel with ethanol in it. Most gas stations have 10% now and that was a big problem on all of my carburated engines.

not an issue all HS ethanol causing problem, it's been out for over 20 yrs all ready. If you've got an extremely old boat that is all gummed up and crap is in the tank you might have some issue, but this isn't the case with Steve's Boat.

FWIW, here is a pic that "UK Roger" took of the engine taken at GL...

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The pcv valve is taped off because of the vent tube from the oil fill cap.

Bottom end is NOT rebuilt...yet...

it has a timing chain..

10% E.fuel is all we can get ....been running it for 6 years..

Plug wires are solid cores ... about 2 years old...not many hours on them.
Plug gap is set at 30 or 35 ..cant remember for sure.. these plugs are a year old... new ones will be in this weekend.

Point gap is 24 per Interceptor manual.. no dwell specs in that manual.. Dwell is running around 37...what ford calls for.

well we are back to prop then, unless the compression is down, the dwell seems high to me thought 30 was about right but if the book states 37 then who knows. Might double check all the intake bolts make sure your not sucking air anywhere, doubt you'll fine any loose since it idles fine, just a realy odd ball probelm.

heres a thought bypass the ballast resistor if it has one, this will give it a hotter spark, see if that changes anything.

Toigs325 wrote: 79nautique wrote: Toigs325 wrote: Make sure you aren't running fuel with ethanol in it. Most gas stations have 10% now and that was a big problem on all of my carburated engines. not an issue all HS ethanol causing problem, it's been out for over 20 yrs all ready. If you've got an extremely old boat that is all gummed up and crap is in the tank you might have some issue, but this isn't the case with Steve's Boat. I have a 2003 196 SE with a holley 4 barrel...it ran like crap for a couple months until we figured out that the fuel we were using had ethanol in it and the carb couldnt handle it. I have also heard that it can cause boiling and overheating.

no you finally got the water out of the gas tank and seperator and bought into a bunch of BS actually, I'll go out on a limb and bet you took it to a dealer and spent about a grand to find out your carb couldn't handle the gasoline blend.

79nautique wrote: well we are back to prop then, unless the compression is down, the dwell seems high to me thought 30 was about right but if the book states 37 then who knows. Might double check all the intake bolts make sure your not sucking air anywhere, doubt you'll fine any loose since it idles fine, just a realy odd ball probelm. heres a thought bypass the ballast resistor if it has one, this will give it a hotter spark, see if that changes anything.

The boat is running about 140 lbs cold compression with this head, up from about 130 with old head. Book calls for 160, altho manual states +/- 20 lbs, so at edge of low range. BTW, I did the comp. test..no plugs/ no carb/ cold motor.


Intake is cast into the head.. no bolts..

as for gas tank, it was cleaned and a liner installed last year.

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Steve check the voltage at the coil, but it's sounding like a new prop, you've been through it and checked about everything to check so there isn't much left but that.

Run BP fuel for years.. (dont like the Shell owner in town.)

Like I say, there may be a little blow-by from the valve cover vent tube, we noticed this at GL.... I'm hoping to do a wet and dry compression test, as well as a cylinder leak down test when I get time.

will also change back to 12x12 and new plugs in.

after that...Lower end .... here I come...

79nautique wrote: after all that is done and if you don't see any changes change the dwell get it closer to 30 and then retime it. Does you ignition system use a ballast resistor?

Chris.. yes it does have a ballast resistor. It was changed last year..I think it was a Chrysler one we used ... it had similar specs to what a Falcon used, if that means anything?

I also thought the dwell was a bit high, I'm used to the SBC's 30 myself. The Interceptor manual has no reference to correct dwell, just point gap of .024. Like I say , the Ford book calls for the 6 banger to have 37 or 38 dwell, of coarse they arent using a Mallory dizzy.