Have you tried pulling the spark plugs and turning it over by hand? It should turn easily. I just can't buy the fact that two starters would go at the same time, unless there was something wrong with the engines. I'm wondering if they might have put in the wrong sized bearings, say for a ground crank when it wasn't ground, or something of that nature. If you can get an induction ammeter, you can hold it on the starter wire and read the amps that are going thru it. I don't remember exactly, but I think it should peak at around 200 amps when very first turning, and then drop from there. If you are pulling something like 600 amps, it is not due to the compression of the engines. If I burned up two starters on engines that were just rebuilt, your damned right I would go right to the builder about it. It simply should not happen, especially two at once. If you can pull one engine, use plastigauge to check the clearances in the bearings. Pull the plugs and turn it with a wrench.

Another vote for timing issues!
 

I put my engine back in the boat three weeks ago. I had it out for some minor mods, oil pan oil cooler. It ran perfectly last year so I couldn't figure out why it wouldn't start when I put it back. It cranked very slow, and chugged once in a while like it wanted to start, but wouldn't quite catch, the starter smoked, the battery terminals melted, etc. Sound familiar? First I thought it was fuel, and spent hours chasing that issue. Then... maybe I don't have spark? Verified spark that's not the problem. Then I thought it was batteries, cause the cable had gotten hot enough to melt the terminals. Got new batteries, still nothing but a slow turning engine. I tried the charger, and boost charge, etc, etc, blah, blah, blah. I spent a good 16 hours in my driveway chasing ghosts on this thing (plus I pissed away $100 on two new batteries, now I have 4). My engine was acting exactly like yours. Finally, I decide to recheck my timing. Crank the engine up to TDC, pull the distributor, and reinstall at 0 deg advance. Crank the engine and she fires immediately!

If you don't do anything else, go back to square one and redo anything timing related. Don't just look at it cause it's to easy to miss something. Talk to your builder about the cam timing. Pull the distributor, wires, etc, and redo the timing. I can't emphasize enough how much my engine was acting like yours, and it was a simple timing issue.

Good luck man!

Bulldog has the correct idea....but it requires the starter to work....do a leak down first! then steve miklos had great advice!....it should take UNDER 1/2 to figure out why this engine does not run....do a leak down!

what's this engine builder have to say at this point????

If you can't turn the motor over to do a comp. test. do a leak down test. I'm with cuda sounds like the motor is to tight. Were the ring gaps checked when the motor was put togeather? Pull the valve covers off and make sure the rockers are opening and closing. are you sure the valve lash was set right? I feel for you bro, GOOD LUCK! On real high comp. motors (which you don't have) they will start spinning the motor over before they put fire to the ing. system. Watch them start a nascar motor next time they use 2 switches. Did you ever try turning the motors over without power to the dist. or with the spark plugs out? Did it still turnover slowly?

All the suggestions have been fantastic, I would have to agree that timing could be the culprit here. Also check the grounding of the batteries, could be a poor ground causing the weakness with the starters and cranking slowly. I second the idea to unhook the hotwire to the distributor and crank, that will tell you if it is spark timing. However cam timing off would cause slowly cranking if its too advanced creating too much cylinder pressure. Is this a multiple keyway timing chain, those are easy to install wrong, been there and done that years ago when I was getting my initiation on boats. Damn thing would hardly turn over. Always remember that the keyway should be at about two oclock when the marks line up and you will not make that mistake. Good luck!

Okay well I called the engine builder.
He said to turn the distributor and I told him I have done that about 10 thousand times and she wont go.
She wants to but wont.
I said im getting fuel, spark and some coughing going on but no Kaboom fires up.
I said she is turning slow and the batteries are good.
he is sending a tech out to my house to go over everything and see what is the problem with them at HIS expense not mine.
Now that is good customer service as far as Im concerned.
I had no problem towing the boat down there but he is coming to me.
not bad
Now funny you said ground
I was charging the batteries on the boat with the charger IN the boat.
My friend was standing on an aluminum step stool looking over the side holding on to the stainless steel rail that goes around the engine hatch
I leaned over to grab the flame arrestor
I grabbed onto the rail that my friend was holding on to and touched the arrestor and got zapped.

Is that normal? I figured since boat was off the ground and my friend was grounded that was why but still seemed strange to me.
But now it is time to let someone else start messing with this so I can have some peace of mind here.
Jason

Okay guys Maybe im not out of the woods yet BUT
I have one of my engine builders service techs coming out to look at what is going on with this thing.
He said and I quote "no problem, we will get these things running for you"
I explained the one starter that the bendix is stuck and he said no that is mostlikely not your problem, you probably have the washer on the one yellow and red stripe wire welded to the solenoid which is causing it to constantly get power from the battery.
He informed me that he can take care of that (guy must have 9 foot arms and not mind getting poked in the chest with a carb stud)
now let me ask this
Since I put on the new goofy silver metal riser gaskets, If I yank off the risers to get access to the starters and other things do I need a new set or can I reuse the old ones?
Once torqued down and they compress that is it right?
no more????? Trash them and start new again?
Suggestions? Comments???
Also this guy seems overly confident in his abilities to get these things started so lets see what he can do
Thurs night baby
Im hoping to report my initial run comes this weekend and I dont care if it does rain, im going out if they run guys!!!!
even for 30 minutes and zip around the mouth of the marina just to get it all moving and flowing and check for leaks and what not, bring it home, make sure everything is nice and tight and retorque exhaust risers, check everything over, change oil again and I should be able to forget about it for a while
so brothers, wish me (or this dude) some luck
Jason

That's cool that he is sending someone out.
I was thinking that you probably had a starter wire on wrong for the starter to turn when the battery switch was on....been there done that :rolleyes: That will be an easy fix if that's the problem !
You say the other starter is fried though? What is keeping it from comming out with the motor in the boat?

Did you ever get over to Bob's to get that impellor kit ? Did you get that installed ?

Good Luck Jayl!! I mean it, not being sarcastic. Sometimes it helps to just back away from a problem for a bit. Then go back with a clear head and start with the BASICS. Probably something very simple and not in plain view because of the twin setup. Take some time and keep us posted when you dive back in.
R' Addiction, (Ike's Brother);)

good luck dude
nab it right in the bathole:D :D