Ralph,
I formulated a plan based on the suggestions given from my friend who is a diesel mechanic and the marina technician and also the very helpful people on this forum. some of The general consensus was that The issue was likely a fuel delivery or starvation issue. Plan was to eliminate and resolve any and all issues that could be from the tank to the injectors.
1. Pick up tube needs to be replaced regardless (38 years old) don’t trust it.
Unfortunately it’s still stuck and I don’t want to force it and break it off, so letting to penetrating oils work there magic.
2. Replaced all fuel lines. they need to be replaced anyway (38 years old ) don’t trust them either, could be restricted or failing internally
3. Replaced fuel lift pump, told that the diaphragm internally could be starting to fail and could have an effect on other components such as injection pump or the governor. So for $40 remove this from the puzzle.
4. Changed the primary and secondary fuel filters even though they only have very little hours on them. Eliminate clogged filters as a possibility.
No big deal, I would have normally replaced in the spring anyway.
5. Checked all fuel supply and return lines on the engine. Eliminated any possibility of a restriction
so far I haven’t broke the bank, just my time and labor so far, and for the most part just replaced normal maintenance items. Plus set up a temporary test diesel can as a fuel tank until I can get the pickup tube out.
regarding the mixing elbow: this was replaced approximately 4-5 years ago and has very low hours on it 20 -30 at best. The old one that was replaced was actually in amazing condition, almost no buildup at all considering it was 35 years old. The only issue I really had was the external corrosion. The consensus from most including Yanmar technician is that it is highly unlikely that it’s plugged up. No overheating, no smoking issues, other than the rpms everything appears to be fine. That being said it will be investigated as a possibility hopefully this spring.
Unfortunately I am still limited as to what I can and can’t do.
I am still recovering from two major surgeries. I am just trying to eliminate some obvious things that could be the culprit along with some things that have been on my to do list.
I’m not a diesel mechanic and don’t claim to be by any stretch, however I am mechanically inclined a have fair idea how diesels work. Hopefully with some insight from my diesel mechanic friend, the marina technician and others on this forum.
I will solve this problem before calling in the big guns and spending money unnecessarily.