Since I was born 77 years ago, I've been a life-long hot rodder and record-holding drag racer. But for my 22' boat I got a 5.7l Blueprint long block from Summit (5.7, 373 HP, Vortec heads, one piece main seal, roller rockers) and the marina mechanic installed it. All of the good parts from the original engine were transferred plus an Edlebrock dual-plan intake, a rebuilt Rochester Qjet (replaced the Holley), a new marine starter, new plugs, new quality spark plug wires, and new Mercruiser manifold exhaust system ($$$ ).

The engine didn't run well from the start. Initial 3-minute test run was pretty good at first, reaching 4800 RPMs at one burst, then the RPMs dropped, wouldn't take throttle, and stalled out. It would run then stall out. Thinking it was a fuel delivery problem, I continued to start and run and stall out ...until I went a short distance to the marina.

The mechanic ruled out a fuel problem, and then had a very difficult time starting the engine. It finally started and the timing was rechecked and my guess is the timing was off before. Not being able to pay more for the marina work, I have been working on it myself for 2+ weeks (I'm fairly capable, and have learned a great deal more from videos and advice online).

Here's what's up and I'm stumped. I've gone over the entire drill many times;

1. TDC on #1 (blows thumb off with aggression, so compression is good on that cyl at least).
2. Dizzy rotor is correctly in time, pointing to #1 tab in the cap.
3. Carb is getting fuel.
3. I removed the DUI dizzy and installed another HEI to see if things would change, but they didn't.
4. New wires are quality, new plugs could be a little fouled now, but not enough to prevent firing.
5. Dizzy is seated properly and the rotor turns when cranking.
6. Wires are on right plugs and terminals 1-8-4-3-6-5-7-2 (this firing order shows up in my sleep).
7. Ignition switch is wired and installed correctly (unless I've got something wrong. 4-terminals; IGN to dist., battery to BAT terminal, wire to solenoid, and gauge connections to ACC terminal).
8. There's 12.6 v at both the ign switch and the dist. terminal.
9. When cranking, voltage drops to 10v, which I understand a good reading.
10. Along the way, I tested spark with a 4-plug tester, and there was ONLY a very weak spark on cyl. 6.

When the engine was first cranked it seemed a few cylinders wanted to start for a moment, but no start. And when I moved the dizzy to maybe catch better timing, it had no effect on trying to start (I'm using a remote starter switch). After the initial 'try to start' mode, it wouldn't try any more, just cranked at any timing adjustment. It turns over at what seems to be the normal speed.

Again, when #1 plug wire is checked for spark with the clip-on tester there is no spark. But it has compression.

Left to do today is run a jumper wire directly from the battery to the dizzy and see what happens. Also check all battery cable and wire grounds and check resistance ohms.

Can you guys understand I'm at my wits end. Working on this engine in the unmovable center console is nearly impossible except for the Qjet and the dizzy. Because of the new risers and elbows on the Vortec heads the plugs are a nightmare to reach, and working in the 92-degree FL sun is no picnic (poor me, eh).

Your help is invaluable. Thanks so much! Larry