Volvo 200D v8 wont start

I am working on a bayliner for a friend. small block chevy, carbureted engines turns over but will not start. distributor was rusted and replaced with an automotive HEI unit. before I started working on it. engine ran 3 years ago last time it was used. compression is 100 to 125 psi on all cylinders , wet with oil compression comes up to 140 . engine has been setting a long time in the weather. I rocked the harmonic balancer back and forth and watched the dist rotor, not much play in the timing chain so I dont think cam timing is an issue. it is a standard rotation engine, so I assume the firing order is standard gm 1-8-4-3-6-5-7-2 ? spark plugs wires dist cap and rotor are new, though they are not marine parts. I verified spark at the plugs. played with the ignition timing, but doesn't even try to fire. I connected the power wire of the HEI direct to battery and verified the dist has a good ground.
there is fuel at the carb and accelerator pump , tried starting fluid as well. still will not fire, not even back fire . I opened the gap of a spark plug to about 3/8 of an inch, spark will jump the gap but is not the bright blue spark I am used to seeing. seems it would be enough voltage to fire under compression. what am I missing? somthing I am overlooking? , my next step is to replace the distributor with a know good unit, just have to find one.

 

First of all, a word of caution. Marine ignition systems must be spark protected. An automotive cap/distributor will likely not have the metal screen to prevent an explosion. 3/8 of an inch is a huge gap. If you still have spark the ignition is fine. Have you checked that the distributor is not 180 degrees off?

 

I will check this evening to be sure its not 180 out, I did hear that cylinder blow as it came up to tdc and checked rotor position, maybe better to do it with the compression gauge hose in and my thumb over the end of the hose. I am going to talk him into the correct marine ignition.

 

It will blow on the exhaust cycle too, but with little pressure. A compression gauge will let you know. Good luck.

 

rotor position was correct at TDC compression, I was able to get it to start finally but could hear every intake valve pop through the carburetor. I did a leak down test, 50 to 60 % leakage. leaking to intake manifold on nearly all cylinders. kind of surprising that the compression was as 100 psi and still have that high a percentage of leakage. wet with oil compression came up significantly. thought it was rings not sealing .

 

You can have high compression results on a worn engine if it has a lot of oil on the cylinders. However, it will use oil and smoke when running.

 

update on the 200d not starting. I started pulling the engine apart, when I pulled the risers off the exhaust manifolds I found someone had made their own gaskets. the gaskets had cutouts for the water passages but not for the exhaust. so the exhaust system was effectively plugged on both manifolds.

 

Ya know, you think you've heard just about everything and then......

 

A couple of pics