HELP!

[Canuck Sailor]

Actually, help wanted... a friend with an A4 is in the Jacksonville FL area and is looking for someone who knows the A4 engine to do some work. The marina mechanic is saying he doesn't work on gas engines, the usual drivel... and it's been my experience that to work on the A4, you need to actually KNOW the engine.
What my chum needs done is replacement of the exhaust and possibly the fuel lines right from the tank. He's seriously NOT mechanical and can't do it himself - and I'm in the Bahamas so I can't help.
It's possible that the exhaust is creating blockage which is affecting the engine's performance - he can't get it to rev above about 1600 or so. It could also be a fuel delivery problem - the lines are over 30 years old. No one has been able to properly diagnose the problem. Compression is 85 - 90 on all cylinders.
If you know of a competent A4 mechanic, or know your stuff and are in the area and want to lend a hand, let me know please. My friend has been dealing with this problem for too long and it needs to be resolved.

[JOHN COOKSON]

Yes, a blocked exhaust and fuel delivery problems will affect performance.
A sticky spark advance or other ignition problems such as a spark plug that is not firing will affect performance.
The engine may be fine. Something may be wrapped around the prop or more commonly the prop may be dirty.

The best thing for your friend to do would be to join the forum and contact us directly. We can suggest simple tests to narrow the problem down.

Your friend may become a great mechanic - he\she may not know it yet. It has been known to happen around here. All knowledge levels are welcome - no one is belittled or made fun of in this forum.

ex TRUE GRIT

[Canuck Sailor]

What is the procedure for dealing with a blocked exhaust on the A4?

[JOHN COOKSON]

What is the procedure for dealing with a blocked exhaust on the A4?

The general answer to the general question you asked, when the area where the blockage is occurring is unknown, is to replace the exhaust system. I think we can do better.

The A4 does not have a unique exhaust system. The builder added the exhaust system as the boat is built. Different builders and different boat lengths have different exhaust system construct to their own specifications.
Let us know what make and model the boat is. Maybe someone in the forum will have a sister ship and be able to offer some specific advice.

ex TRUE GRIT

[Dave Neptune]

CS, dealing with a blocked exhaust is a waste of time unless a collapsed hose is the issue other than that just replace with iron pipe unless you have a custom installation like a stainless riser manufactured to suit. AND I seriously doubt that the original exhaust is still in place after all these years.

The cobbling together of the pipe and hose is not that difficult to do but can be a bit time consuming going back and forth getting cut lengths and elbows.

If your hose looks suspect I'd replace it too as they can collapse inside and you can't see it on the outside.

Start with a new manifold fitting as they can be an absolute bear to separate and you will wind up destroying it anyway.

Dave Neptune

[ndutton]

Exhaust system replacement is the same work as disassembly and inspection. I like McMaster-Carr as a source for schedule 80 pipe and they have it in 316L stainless steel as specified by the USCG. A few clicks online and the parts are delivered to your front door.

The sealant pictured is rated to 750°F, also available from McMaster-Carr. Recommend you replace the exhaust manifold flange bolts to stainless studs and external hex nuts. You'll never have to deal with a frozen bolt again.

[ronstory]

In a pinch, if you can't source Neil's graphite paste, ordinary stove pipe cement from a big box store works well.

https://www.homedepot.com/p/Rutland-10-3-oz-Furnace-Cement-Tub-in-Black-64C/202218155

[Canuck Sailor]

@NDutton and Dave Neptune - if I understand you two correctly, one has to measure and have cut the appropriate sizes to make that lovely looking setup in the photo?
Can you be more specific as to ID, OD, lengths, etc? I'm nowhere near my chum's boat to do this myself - he's in FL and I'm in the Bahamas.
And is this the page for the material required? I don't see sched80 pipe listed. Wait - found the sched 80, but can't find SS elbows. https://www.mcmaster.com/standard-pi...pipe-fittings/
I guess I'm asking you for a parts list, if you have one

[Sailorchris]

Thanks for the advice.. It's my boat..

1975 Pearson 35...

It's not that I don't want to work on my boat and learn its that I physically cannot maneuver my body into the engine compartment I recently had a hip replacement I'm almost a hundred percent but I can't get in there yet.

In the meantime I'm stuck on a dock I cannot stay on and I need to get it repaired replaced and get off their dock as soon as possible

[ndutton]

Scroll down to the bottom of this page:

https://www.mcmaster.com/standard-pipe-fittings/stainless-steel-pipe-and-pipe-fittings/thick-wall-stainless-steel-threaded-pipe-nipples-and-pipe/pipe-size~1-1-4/

and pick the sizes you want.

The elbows are their part #4464K17, the sealant is their part #4586K8. I made the integral water injection fitting myself but Moyer Marine has one in their catalog for those who don't want to go the extra mile of welding stainless. Moyer also has the pipe wrap fabric.