Seasport owners

I

iain

New Member
Hi
I've got a new to me 24' seasport explorer 1998 with a volvo Ad41p with dpe 290 drive.
I've got a few questions that I'm hoping you guys on here will be able to answer.

1. I run it at 3200rpm and it cruises at 15-16 knots. Does this seem normal for this size/weight of boat with this engine. It has aluminium pros.

2. What would I expect to burn in gph cruising at 3200rpm?

Thanks
 
Hey Iain.

That does not sound right. Is it a dual prop?
I had a 2700 Navigator Seasport with the same engine. It had the duo prop 290 drive.
I did 22 knots (25mph) at 3200 rpm. My boat probably weighed close to 8000 pounds..
Wot is 3400 to 3600 rpm so your boat should be able to achieve that. If not your over propped.
Cruising rpm is 200 rpm below wot but I found 3000 to 3200 the sweet spot.

I put stainless props and got about 2mph faster at same rpm.

The AD41 is a great engine. Really liked mine. Burnt about 5 gph at cruise which is amazing.

There is a SeaSport Rendezvous in Friday Harbour August 24, 25, 26th. Everyone is welcome.

Cheers!
 
it is a dualprop. I wonder what the issue could be. I can hit 3900 rpm at WOT. Takes the turbo to kick in before it even thinks about getting on plane.
I figured it seemed kinda slow. Could my tach be way out of calibration?
 
other issue I'm having is with the raw water pump.
Put the boat in the water the other day. Started engine and cracked strainer cover and water started pumping. Went out and ran boat for 1 hour. Coming in to dock the temp kept climbing to over 200 and I had to open strainer cover again. Seems I lost prime. Ran the boat all weekend with no further issues, cruising at 3200-3300rpm (temp 180) and at idle with no further issues docking.

Pulled the boat out. Went to flush engine at home and couldn´t get any prime on the muffs. Submerged leg in tub. Still no prime. Pulled off pump cover and impeller looks in good shape. Pump cover has obvious wear pattern from impeller. Is this enough to cause an inefficient pump? Is there a way to reface the cover? Its the type with the o-ring, not gasket.

Whats the best way to test intake side of pump for leaks? Plug the hose at the leg and pressure up with water or air and check hoses and fittings for leaks?
Or is it just time for a new raw water pump?
 
You don't want to replace raw water pump on a guess. Just priced one out as I am trying to diagnose a cooling water flow issue to. The pump is a $950.00 item. Did you change the impeller? It can look okay, but unless you pull it you can't see if the vanes are starting to weaken.
 
no need to replace the whole pump, just replace the impeller, as sin bin said the vain will harden and you will loose suction. i have a pressure gauge on the pump, but i am going to put a flow alarm in instead.
 
K. Thanks. I'll check out the impeller more closely when I'm back from camp.
I like the gauge idea though. Where exactly did you mount it?

The previous owner said he always has to open the strainer lid to remove airlock after its been out of the water. Does this seem normal or is this a sign of an inefficient pump?
 
Pretty common. Opening the strainer removes an airlock and primes the pump. Put your hand on the exhaust elbow where the raw water cooling line attaches to the shower nozzle and if it is getting warm crack open the strainer lid close it when the water starts to come out the loosened cap. The elbow should start to cool when flow is established.
 
iain said:
K. Thanks. I'll check out the impeller more closely when I'm back from camp.
I like the gauge idea though. Where exactly did you mount it?

The previous owner said he always has to open the strainer lid to remove airlock after its been out of the water. Does this seem normal or is this a sign of an inefficient pump?
Click to expand...
there was a port in the back of my pump. this was a sherwood pump in a cummins
 
K. Thanks.
I'll have a look. Wasn't pumping any water when I last tried to run it. Nothing when I opened the strainer lid. Impeller must be toast or I'm sucking in air somewhere.

And have to check if the tach is out of calibration too. Does the factory Volvo tach have an adjustment if it isn't reading correctly?
 
Sir Reel said:
Hey Iain.

That does not sound right. Is it a dual prop?
I had a 2700 Navigator Seasport with the same engine. It had the duo prop 290 drive.
I did 22 knots (25mph) at 3200 rpm. My boat probably weighed close to 8000 pounds..
Wot is 3400 to 3600 rpm so your boat should be able to achieve that. If not your over propped.
Cruising rpm is 200 rpm below wot but I found 3000 to 3200 the sweet spot.

I put stainless props and got about 2mph faster at same rpm.

The AD41 is a great engine. Really liked mine. Burnt about 5 gph at cruise which is amazing.

There is a SeaSport Rendezvous in Friday Harbour August 24, 25, 26th. Everyone is welcome.

Cheers!
Click to expand...

Sir reel
Do you think our drives would have a different gear ratio? Do you know where I can check this? Do you know what prop size you were running?
Thanks
 
Last edited:
I had A3 props and then changed to C3 stainless. Sorry don’t Remember the gear ratio.

I am wrong about the max rpm on the 41. I was thinking of my new Volvo engines.
Yours should be 3800 to 3900 rpm. So yours sounds good.

I always had problem with muffs on the leg and could not get them to seal right so I would duct tape them to seal better.

I trailered mine and never had a raw water pump issue. I did put a new impeller in every year. Cheap insurance.
You will also have wear marks inside the pump walls however I have heard it can wear so much it is not as efficient.
I had my boat from 800 hours to 1150 hours with no engine problems. Ran Amazing
My boat too would not get even near plane till turbo kicked in and then we were off!

I have been told by many people and mechanics that the 41 series was the best engine. Simple mechanical design and no electronics. Good for 8 to 10,000 hours easy. They use that same engine in a dual configuration in a lot if the Commander 30’s too.
 
Thanks for the info sir reel.
Mine still sounds like it's slow doing 15 knots at 3200 rpm. Can't weigh more than 7500lbs with fuel and water on board.
I'll have to check the accuracy of the volvo tach next time I'm out on the water. Once I'm pumping raw water again that is.
 
Ya that speed is too slow for rpm. Maybe your props need tuning. Is that speed via gps?
I picked up about 3mph when I did the props on my Commander.
 
i hate to say it but it could be a slipping coupler?
 
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