Beta Marine slow to start

[Popeye2]

Betamarine engine (20hp) 15 years old. Slow to start. After cranking for about 15 seconds it starts. For the rest of the day it starts first time. Engine not blowing smoke except in high revs. Makes a ticking sound.
The Fuel filter was too loose and caused fuel to leak. Its tight now. Tried bleeding from that bleeding screw (see photo). Does not seem to have much effect. When loose, under cranking I do see some bubbles. I never see fuel coming out of it. That screw is not the original. The head of that original one broke off . I just put that alan bolt in there.
Is it so that , when there is no air in the fuel line, fuel will come out here?
Will any old bolt do or is it to be a certain length?

A mechanic visited some time ago (before I noticed the leaking fuel) and said the cause of the slow crank was blocked exhaust. He confirmed this by producing black sooth at high revs. He advised I change the exhause manifold. I ordered a new one . The old bolts holding the existing one, the heads of the bolts broke. So at the moment its stuck in there.
Think is, another mechanic said that is unlikely to be the cause, and indeed I had a look into the exhaust elbow and it was clean. And the engine always produces sooth at high revs because the propeller is too big. (I kept the prop on my old saildrive, just cut it down in size a bit to try and suit the newer engine and its still too big)

[a64pilot]

It’s likely low compression or at least sounds like it.
The ticking sound needs investigating I think, maybe valves are out of adjustment and if so they can cause hard starting and are easy to check.
I’d start there, from there I would proceed to having the injectors serviced and a compression check

[nhschneider]

I don't know if that engine uses glow plugs or not. If it does, I think that's were I would check first.

The black smoke - soot - at high RPM might be caused by the prop having too much pitch. Does the engine get up (or, at least, close) to its rated speed when running at Wide Open Throttle?

I used to have a Westerbeke genset that seemed to crank forever before it would start. Even though I tried hard to fix the problem, I was never able to get it to start quickly.

As a suggestion, I'd recommend that you get the broken manifold bolts (studs) repaired.

The Allen screw you put as a replacement for the bleed screw in your injection pump is probably fine.

Fair winds and calm seas.

[Popeye2]

Originally Posted by a64pilot

It’s likely low compression or at least sounds like it.
The ticking sound needs investigating I think, maybe valves are out of adjustment and if so they can cause hard starting and are easy to check.
I’d start there, from there I would proceed to having the injectors serviced and a compression check

Thanks

[Popeye2]

Originally Posted by nhschneider

I don't know if that engine uses glow plugs or not. If it does, I think that's were I would check first.

The black smoke - soot - at high RPM might be caused by the prop having too much pitch. Does the engine get up (or, at least, close) to its rated speed when running at Wide Open Throttle?

No. More than half trottle creates too much sooth.

I used to have a Westerbeke genset that seemed to crank forever before it would start. Even though I tried hard to fix the problem, I was never able to get it to start quickly.

As a suggestion, I'd recommend that you get the broken manifold bolts (studs) repaired.

Seems difficult.

The Allen screw you put as a replacement for the bleed screw in your injection pump is probably fine.

Fair winds and calm seas.

Thanks

[keith001]

Try adjusting the valves.