Engine room air intake blower replacement 2001 34 convertable

Welcome to the forum. If the blower is truly inaccessible, you may just have to abandon it and install one in a more accessible location. Many of these engine rooms items are installed before the deck and cabin join the hull upon production, sometimes resulting in impossible repairs locations. Hopefully another Luhrs owner will give you other/better insights

You should first determine if it is for bring air into the engine room or removing fumes or hot air from the space. There is no typical marine inline blower that can bring in enough air for engine combustion, so figure out the purpose before going forward.

Good point. I made the assumption OP was speaking of an exhaust unit that removes fumes and a little hot air. Post's installation has one intake and one exhaust on each side on the theory that those opposing units provide circulation. One has an extension hose that comes down the inside hull a bit Also have oscillating 110v fans to move the air across the hot engines

There is always a way to get to something.

How do they do the test for engine room lack of air flow? I am guessing a vacuum gauge of some sort to make sure there is enough air entering for top rpm .
Are there any easy DIY tricks?

The old way to notice poor engine room intake air opening sizing was running at high cruise and having difficulty opening the engine room door or hatch due to the large negative pressure induced by the engine sucking all the air out of the space. The other tell on older SF with engines under the salon with hatches covered by carpet were clear indentions/outlines of the hatch in the salon.

Nowadays, a lot of systems monitor Engine Room Air Temp and adjust the air flow accordingly.

You can talk to Delta T for additional information: https://deltatsystems.com/system-engineering-design/

If you have gasketed hatches,can you open them easily underway?

I have plenty of airflow now, I have the 40 open so my intakes are in the fishing cockpit just wondering if during the colder months I could close them off partially or entirely and still maintain enough air flow into the engine room.
I guess I could make covers for them and try to install and remove while running to see if it creates a vacuum.

What is your goal in closing them off in colder weather? The air flows into the warmer engine compartment,

Noise, maybe even add some tackle storage there and make the vents smaller.

Diesel engines love cold air, makes them happy and gives them a bit of a power boost. Not talking freezing temps, just normal winter recreational boating weather.

The formal way to monitor the engine room is with temp gauges tied to an appropriately sized fan system and engine room vent openings. One temp gauge outside the engine room to monitor ambient air temp , one inside the engine room, preferably up high forward and aft to get an average, and measure the difference. If the temperature drop between ambient and the engine room is greater than 30 degrees, you need more air flow - bigger vents, bigger fans or more removal of air in the hot engine room.

Put some acoustical material in your engine compartment? IMO, don't fool with your air supply

called a saws all?

In small production sportfishers your engine room air vent openings can never be too big and are usually undersized. You want the system sized for August, not February temps.

Noise is another issue with different solutions than closing off air vent openings.

I have checked my engine room temps in the middle of summer they are fine. I would probably remove any tackle storage or covers Etc from the vents during the full heat of Summer.
My main question was measuring adequate air flow. Just wondering if I could give up some and still have plenty.
A simple baffle will probably help with engine noise but if I could add some tackle storage why not?
Hence my questions.

If you don't have adequate airflow you will see a rise of temperature in the engine room greater than 30 degrees from the ambient outside temperature. This is how you check - do you have remote thermal probes in your engine room that can be read at the helm? Engines pull the air in, and hot air leaves by convection or by fan assist.

What engines do you have - they are usually pretty clear on their air supply requirements and engine room temp limits?

LOLOLOLOL Lord No!!!! By removing something to get to something else, by approaching it at a different angle, by finding someone that's 5'5 to change it while you hand them tools. etc.

Generally, if there is only 1 engine room blower, it blows out. So you can exhaust hot air after the motors are shut off etc.

PacBlue, yes I put a thermometer that I could read from the helm in the engine room last year and watched it all year.
Even In The Heat Of Summer the temperature stayed under Yanmar maximum temp recommendations which seems to be around 120 - 125 degrees
My max temps were under 120 even on 95 Degree Days.