Hard Starting when hot -FIXED!!

All right guys. I've read every post I can about hard starting and I believe I have a problem not previously described. My 85 SN, w/351W will start up fine at launch and run great for an hour or so. High speed, idle touring, etc. Then all of a sudden it's like she can't get any gas and the motor quits as I try to accelerate. Here are all the new(not rebuilt) parts:
Fuel pump, Holley 4160, Mallory Electronic Distributor, wires, plugs, coil, ballast resistor.
Once I open the hood for awhile I can get it started again, and after it cools down even more it runs fine again. Could it be as simple as a fuel supply problem from the tank that develops after an hour of running? We haven't been skiing yet, just driving around on $4 gas.

That's kind of what I was thinking Tom. At least then I could possibly narrow it down to the fuel tank and the fuel line.

Check valve the same as the anti-siphon valve?

Tom

Just a suggestion...might not fit the problem, but check your fuel water separator. You might be getting water in your gas.

cracking the cap won't help the anti-siphon valve is at the begining of the full line on top of the tank.

Hello MdFooter, I just posted a similar post regarding my '77 A few minutes ago. It's funny that before I posted I read quite A few hard start posts but none seemed to apply to me. Wonder if you are having the same problem that I am?
I'm quite confident that someone here will point us in the right direction.

Dawg2001 wrote: MDFooter, you might check your exhaust hoses. If you have a crack in one or both, when it warms up, your getting steam and exhaust in the compartment. Your carb can't get enough air.

what the hell are you talking about, if they are cracked they'll be filling up the bilge with water, way out deep in left on this one.

I thought about the suction problem so I did open the tank the second time out after it quit running to see if I would hear a wooshing of air into the tank, but there was no suction problem and it still wouldn't start.

I've gently pulled the tank forward to check/replace all the fuel lines and am replacing the fuel/water separator assembly. I haven't found anything that seems like an anti-siphon valve at the top of the tank, just the welded-in tank pick-up and the hose barb. Is something else supposed to be there? Also vent line is clear from tank to hull. Thanks for all the good tips so far!

I just want to ski!!

Well I guess I have been sufficiently chastised about the cracked hose post. However, last year one of my hoses cracked on my "85" 2001 and it did not throw out enough water to fill the bilge but it did emit enough "water vapor" and exhaust fumes to starve my engine of air. I did not have a cooling problem but as the cooling water escaped through the crack it atomized into a fine mist.

The Final Answer:

It turns out the problem was electrical. I put in a different coil, one specifically needing an external resistor, replaced the alternator after discovering only +11.5VDC with the engine running, ran new wires to the ignition circuit and back, and replaced the key switch since I was losing .5V across the switch. I also disconnected and removed the electric choke.

Ran great all night both slow speed and high speed. +13.5VDC on the charging circuit and restarted every time. Thanks for all the help!!

OUCH! mdFooter , this was what brainard was talking about in a post about throwing parts and money into a repair before exact problem was diagnosed.You just spent a ton of money to fix a problem that should have been corrected at a lot less cost. I am sure you are getting your 85 in tip top shape and love it but you may not have needed all those new parts at this time. I bet she sure looks good when you raise the engine cover though. and you may be trying to get the ol" girl in mint condition as well. Good job finding the problem I know its frustrating to figure this stuff out some times. I once overhauled a motor when it probably was just the fuel pump . But it had a lot of miles on it and I planed on keeping the vehicle anyway. And it ran good after the rv cam was installed, and towed the ski boat better too.

I started with the stock cam in a ford van with a 351. I overhauled it went back with stock pistons/rings crank etc. but put a crane cam in that was 280 duration and 480 lift. At the time they called it their rv/ truck cam for towing etc. I also found cast iron ford factory headers that were used on the hypo mustangs back in the 60's. Exhuast ports were alot bigger than the old stock manifolds at the time. Had a custom y pipe made and had 3" exhaust with a flow master sure woke up that old tired motor up.

another one last week was a 60hp out board (same principle) it cranked and no start, once again the armchairs starting diagnosing it, I merely took a can of starting fluid and gave it a quick shot and it fired (not recomended) the customer told me no spark and was standing right there, why did it fire if it had no spark? i narrowed it to a fuel problem and concentrated on fuel not spark.
the week before i sold him a fuel line and primer bulb and i noticed the arrow was towards the fuel tank, I stopped right there and let one of my guy's loose on it to see if he could figure it out....the clock was ticking, 1/2 hour goes by and he has the fuel pump apart, the screen apart, sure as *************** he couldnt find the easist problem in the world,
you have to approach these problems with the attitude of "if this does this what will this do" I cut him short and told him the problem.
bring me a cold 12er at the end of the day, how could i possiblty charge the guy

Booty,
I hear what you are saying but all the expensive parts were replaced for other reasons before I had the problem. It wasn't until I got the boat home after buying it that I realized some previous owner had run it in saltwater w/out a freshwater kit. Corrosion and neglected maintenance all over the motor. To just change the plugs required pulling a head after one plug snapped off from too much rust around the hex. I decided to replace the distributor after the stock pertronix turned out to be so corroded that the mechanical advance didn't work. The secondaries on the Holley were also completely seized and to save time, since it was already June, I made the plunge for a whole new Holley. So my biggest blunder was settling for this boat and not being more objective about it, and being a little too quick on the point and click at Summit and not making sure all my parts matched. You're right, it's too easy to get caught up in ordering more parts without doing a thorough diagnosis. But the only duplicate parts I have are the wrong coil, a left hand distributor gear for a Mallory, and a Holley 4160 body that might be salvageable with some patience. All the other parts were junk anyway. It looks a little better now but really needs paint everwhere. The picture shows what I had to start with.

A mug only a CCFan could love!



The really expensive parts I have put off. My heads are weeping externally and are dripping water on my new head bolts and spark plugs, and I can just imagine what condition the block is in after so much saltwater. I check the oil after every time out and there is no water in the oil. For now, my only cash burn is for gas and I hope to get a few months/weeks of skiing in before the cold weather comes or something major breaks. Then I will tear down the engine and slowly give it the once over it needs.

Any thoughts on using a good recycled 351W automotive engine block as my starting point?

I wasn't trying to bash you I saw your diary on the boat and realized you were might be trying to spruce the ol girl up. After seeing your engine ,it looks like a friend of mine"s ,lots of salt water,lots of neglect. My buddy has had 3 motors in his boat since 1988 not because he is a motor junkie either. I can't even shame him into taking care of it.Mine isn't perfect by any means but I keep it clean and maintain it., and it does have some problem areas. Motor could stand to repainted it's an older restoration from 1992 and time and wear and tear or starting to show.YOur interior looks great and you will get your motor in shape. You might invest in a sand blaster to clean up all your parts as you rebuild. You will be amazed at what a little cleaning and paint will do. Your block may be ok to use for the rebuild , the heads looked pretty rough with corrossion , hey gt 40"s in the future.