<![CDATA[Cruisers & Sailing Forums - Engines and Propulsion Systems]]>

<![CDATA[Cruisers & Sailing Forums - Engines and Propulsion Systems]]> https://www.cruisersforum.com/forums/ Gas, diesel, hybrid and electric en Wed, 17 Jun 2026 02:57:39 GMT vBulletin 60 https://www.cruisersforum.com/forums/images/misc/rss.jpg <![CDATA[Cruisers & Sailing Forums - Engines and Propulsion Systems]]> https://www.cruisersforum.com/forums/ Which Racor diesel filter copy from Aliexpress is good quality for Volvo D2-50F https://www.cruisersforum.com/forums/f54/which-racor-diesel-filter-copy-from-aliexpress-is-good-quality-for-volvo-d2-50f-300715.html Mon, 15 Jun 2026 16:28:20 GMT Hi all, I wanna switch out my crappy CAV dieselprefilter for both Volvo D2-50F to Racor Filters and install 2 Racor prefilter per engine. As 4... Hi all,
I wanna switch out my crappy CAV dieselprefilter for both Volvo D2-50F to Racor Filters and install 2 Racor prefilter per engine. As 4 original Racors cost a Fortune is there an aliexpress or other copy of the racor that's good quality and can be used? There are hundreds but is there one you use in person or install in other boats orknow itsa good copy.
If possible links please? ]]> Engines and Propulsion Systems CaptainRivet https://www.cruisersforum.com/forums/f54/which-racor-diesel-filter-copy-from-aliexpress-is-good-quality-for-volvo-d2-50f-300715.html yanmar 3Hm35F diptick https://www.cruisersforum.com/forums/f54/yanmar-3hm35f-diptick-300709.html Mon, 15 Jun 2026 07:55:07 GMT the rubber stopper of our dipstick for our yanmar 3HM35F has finally shrunk too much. this dipstick is difficult to find but the dipstick for the... the rubber stopper of our dipstick for our yanmar 3HM35F has finally shrunk too much. this dipstick is difficult to find but the dipstick for the GMs are available. Has anyone tried this substitution? We can recalibrate as long as the stopper holds and its not too long.. . ]]> Engines and Propulsion Systems longtermcruiser https://www.cruisersforum.com/forums/f54/yanmar-3hm35f-diptick-300709.html Universal M40 (1992) dies after 1-20 mins of hight RPMs https://www.cruisersforum.com/forums/f54/universal-m40-1992-dies-after-1-20-mins-of-hight-rpms-300602.html Mon, 08 Jun 2026 11:20:33 GMT Even if we run it at 1100 rpms, this 36hp diesel will die after 5-45 minutes. I suspect the electrical fuel pump as the pumps seems to make a... Even if we run it at 1100 rpms, this 36hp diesel will die after 5-45 minutes.
I suspect the electrical fuel pump as the pumps seems to make a variety of different noises when operating.

- Fuel filters are new, I just changed both and no difference
- My other suspicions are 1) air leaking in from the plunger top of the Graco Fuel filter and 2) the fuel pick-up in the tank.

Has anyone solved this issue of higher RPMs dying engine? A Catalina 35 on my dock has the same engine and same problems (his has gravity feed, no electrical fuel pump) ]]> Engines and Propulsion Systems Trailz https://www.cruisersforum.com/forums/f54/universal-m40-1992-dies-after-1-20-mins-of-hight-rpms-300602.html <![CDATA[Yamaha T25 vs T9.9 on a 45' Cat]]> https://www.cruisersforum.com/forums/f54/yamaha-t25-vs-t9-9-on-a-45-cat-300598.html Mon, 08 Jun 2026 04:25:04 GMT Hi everyone, I am currently facing a dilemma choosing between the Yamaha T25 and T9.9 as auxiliary/backup power for a 45-foot cruising catamaran... Hi everyone,

I am currently facing a dilemma choosing between the Yamaha T25 and T9.9 as auxiliary/backup power for a 45-foot cruising catamaran (9 tonnes).

While researching, I noticed a critical technical change that many might have overlooked:
When Yamaha upgraded the T25 to EFI in 2017, they consolidated the lower unit with the standard F25.
As a result, the gear ratio was altered from the heavy-duty 2.42:1 down to 2.08:1 (the same as the standard F25). Furthermore, the prop diameter was reduced from 12-1/4" to 10-1/4".

Can we really call the new EFI T25 a true "High Thrust" engine anymore?

By pushing a smaller prop at a higher RPM, it seems prone to excessive slip and cavitation when trying to move a heavy displacement hull, especially at lower cruising RPMs (e.g., around 2,500 RPM). On the other hand, the T9.9 still retains its legendary 2.92:1 gear ratio and swings a larger 11-3/4" prop, which grips the water beautifully at lower speeds.

Here is a quick comparison of the specs:

Feature Gear Ratio
Past Carbureted T25 (True High Thrust) 2.42 (before 2017)

Current EFI T25 (F25-Based Consolidated) 2.08 (after 2017)

Current T9.9 (True High Thrust Retained) 2.92

Given that these will be used primarily as backup/emergency power (or for low-speed eco-cruising around 5 knots to complement an electric setup), I am seriously leaning toward the T9.9 despite the lower horsepower, purely due to the superior lower-unit geometry and hydrodynamic efficiency.

I would love to hear your experiences, thoughts, or opinions on this. Am I overthinking the gear ratio change, or is the new EFI T25 indeed a compromised "High Thrust" engine for heavy catamarans?
Is there any other dependable high thrust outboard engine replaces those two models?

Thanks in advance for your insights! ]]> Engines and Propulsion Systems baefam https://www.cruisersforum.com/forums/f54/yamaha-t25-vs-t9-9-on-a-45-cat-300598.html Volvo Penta D2-55 MDI Battery Alarm 3:10 Mystery https://www.cruisersforum.com/forums/f54/volvo-penta-d2-55-mdi-battery-alarm-3-10-mystery-300549.html Fri, 05 Jun 2026 11:03:04 GMT The Mystery of the 3:10 alarm. My battery alarm goes off 3:10 minutes after starting every time. I can silence it and it stays off. But, being... The Mystery of the 3:10 alarm.

My battery alarm goes off 3:10 minutes after starting every time. I can silence it and it stays off. But, being human, soon I will be just silencing it and not checking what it is, and that can lead to bad things.

I replaced house batteries with LiFePO4 and changed the dual alternators to Arco Zeus, all charging to house, added DC-DC XS50 to feed the starter battery. Also many wires, fuses, shut offs, shunts and more were changed at the time. I am proud to say that thanks to all the research I did and advise I got, it went very smooth, not counting 1 alarm.

But I can not see anything that changes at 190 seconds after staring that would explain the alarm. Alternators come on 30 seconds and 60 seconds after start and each take 30 seconds to ramp up. I can watch the voltage from Zeus controllers, Mppts, shunts and even my multi meter at the battery.

During testing at idle. House Battery 13.4, Starter Battery 13.2, Alternators 13.6.

Obviously I did something wrong, the mystery to me is what. ]]> Engines and Propulsion Systems blackwell68 https://www.cruisersforum.com/forums/f54/volvo-penta-d2-55-mdi-battery-alarm-3-10-mystery-300549.html Volvo Penta 2002 engine oil https://www.cruisersforum.com/forums/f54/volvo-penta-2002-engine-oil-300537.html Thu, 04 Jun 2026 17:25:55 GMT Hey all,

I have a Volvo Penta 2002 engine built in 1985. The manual says to use SAE 20/W30 oil but of course that's impossible to find nowadays. What are people using as an alternative? I'm usually operating in 10degC to 25decC temperatures.

Thanks!
Trevor ]]> Engines and Propulsion Systems trevor.harris https://www.cruisersforum.com/forums/f54/volvo-penta-2002-engine-oil-300537.html Beneteau GT50 with Volvo IPS 600 — prior water intrusion / full reseal https://www.cruisersforum.com/forums/f54/beneteau-gt50-with-volvo-ips-600-prior-water-intrusion-full-reseal-300533.html Thu, 04 Jun 2026 02:20:49 GMT Hi all, thank in advance for your opinions.

I’m considering a 2018 Beneteau Gran Turismo 50 with Volvo IPS 600 pods. The boat had documented water intrusion in both drives in 2025. The shop pressure-tested the drives, found leaks at the steering sections, removed both drives, performed a full reseal, replaced shafts due to seal wear, replaced gear coolers, flushed lines, refilled oil, aligned the drives, and splashed the boat with no issues reported.

The seller says it was not a grounding or sitting-on-bottom event — just leak/seal/shaft wear found during service. They also claim the repair has a warranty left and should be good going forward with normal 200-hour oil changes/inspections.

For those who own Volvo IPS boats, especially Beneteau GT / Swift Trawler / similar boats:

Would this repair history scare you away, or would you consider it acceptable if a Volvo IPS survey, VODIA scan, pressure test, sea trial, and oil samples all come back clean?

Also, what would you specifically ask the servicing tech or surveyor before moving forward? ]]> Engines and Propulsion Systems kmires https://www.cruisersforum.com/forums/f54/beneteau-gt50-with-volvo-ips-600-prior-water-intrusion-full-reseal-300533.html Potential fuel problem https://www.cruisersforum.com/forums/f54/potential-fuel-problem-300450.html Thu, 28 May 2026 19:15:41 GMT We took a sample off the bottom of our diesel tank, after it has been sitting 2/3 full all winter in water at 5-10 deg C on the BC coast Referring... We took a sample off the bottom of our diesel tank, after it has been sitting 2/3 full all winter in water at 5-10 deg C on the BC coast
Referring to attached picture, there seems to be a few teaspoonfuls of water at the bottom.
Our tank is integral with the hull, and the low spot is very small, so water gathers locally.
There no water visible in the filer bowl (twin Racors_)
The diesel suction point in the tank is about 25 mm above the bottom (about 10 litres worth, so I would not expect it to pick up the small quantity of water.)
We are concerned about the cloudy nature of the sample. Chat GPT and Gemini say it may be emulsified water , and could damage the engine
Ours is a Beta 60 (Kubota block)

There are 240 litres diesel in the tank.

Opinions on what to do?

We could run and change to the other Racor if it plugs.
Any magic potions to make the water separate out?

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]]> Engines and Propulsion Systems nmccubbin https://www.cruisersforum.com/forums/f54/potential-fuel-problem-300450.html Rheinstahl Hanomag D351, keel cooling, identification and suggestions :0 https://www.cruisersforum.com/forums/f54/rheinstahl-hanomag-d351-keel-cooling-identification-and-suggestions-0-a-300423.html Wed, 27 May 2026 08:45:56 GMT Hey all you kind folks :)

My German gf recently got a hold of a custom build mono thirty something ft'er. It's somewhere in the deep south of Bavaria, or north. She's been sending me pics of her diesel. It's a Rheinstahl Hanomag D351 (ml). She says it's keel cooling, so the cooling loop doesn't use a heat exchange. Neither raw water. But there's a hose that goes into the white chamber before the exhaust that I am a little confused about. If there's no raw water then it's only a dry exhaust but is it just overflow or a cooling for the exhaust?

Are these things that unreliable in cooler weather as I've heard mentioned before? How many attempts you get on a 12V 900CCA starter battery before you are SOL? What mitigation can be made to make it more reliable on a budget? Are glow plugs a possibility or extremely technically demanding?

Thanks for any suggestions or recommendations. Any advice is welcome :)

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]]> Engines and Propulsion Systems Whiteoil https://www.cruisersforum.com/forums/f54/rheinstahl-hanomag-d351-keel-cooling-identification-and-suggestions-0-a-300423.html Diesel system https://www.cruisersforum.com/forums/f54/diesel-system-300416.html Wed, 27 May 2026 00:32:36 GMT How do you deal with algae growth in your diesel system? How do you deal with algae growth in your diesel system? ]]> Engines and Propulsion Systems pzmaria https://www.cruisersforum.com/forums/f54/diesel-system-300416.html <![CDATA[Volvo MD7A won't rotate through 360 degrees]]> https://www.cruisersforum.com/forums/f54/volvo-md7a-wont-rotate-through-360-degrees-300403.html Mon, 25 May 2026 18:00:43 GMT Old engine. Has not been run in 37 years. I bought it 11 years ago. The flywheel will rotate about 180 degrees, but not a full 360. ... Old engine. Has not been run in 37 years.

I bought it 11 years ago.

The flywheel will rotate about 180 degrees, but not a full 360.

When I bought it there was water in the oil (grey oil); I changed the oil and set it up. I noticed it had a bad water pump.

When I bought it I don't remember if the engine would roll completely through a 360 degree cycle by hand.

I have tried to rotate it with and without the compression lever engaged. Nope.

I can put a wrench on the flywheel, but it still won't move through the stuck point.

When I just rotated it I heard a tiny bit of crunching.

There is some rust when looking through the oil fill hole into the rocker cover/valve cover---it appears to be a normal amount of rust.

Sorry. I don't have pictures yet; I left my camera at home.

Your thoughts. ]]> Engines and Propulsion Systems esarratt https://www.cruisersforum.com/forums/f54/volvo-md7a-wont-rotate-through-360-degrees-300403.html Volvo TAMD30A (?) https://www.cruisersforum.com/forums/f54/volvo-tamd30a-300338.html Fri, 22 May 2026 02:25:00 GMT G'Day all. Long story short, ive been helping a mate with his Volvo. Black smoke led me to the exhaust bend which wasnt too bad.
However the turbine had dropped off the shaft blocking the works!.. It had been rebuilt at some stage and a decision was made to just bypass it.
Plug the shaft bore and keep the housing for exhaust mounting, water injection etc and let the oil run through...
You can guess the rest.

Plug didnt plug and it ran away on its oil. Almost all of it before i managed to block the intake.
Noisy, smokey and a bit frightening.

Now the intake side is gone and I've put a plate over its mating half. Plugged the oil feed at the block
and capped the return to the sump. Oil is at 80psi on the gauge and running sweet.

My question is should i have plugged the feed or tried to let it circulate as it did with the turbo installed.
80 Psi seems high for a fairly old motor but within specs apparently. Gauge could be dodgy i spose...

Any input much appreciated . Cheers. ]]> Engines and Propulsion Systems Happy Max https://www.cruisersforum.com/forums/f54/volvo-tamd30a-300338.html Saildrive shaft seal failure https://www.cruisersforum.com/forums/f54/saildrive-shaft-seal-failure-300312.html Tue, 19 May 2026 20:43:23 GMT My boat is from 2018 and the propulsion system has 850 hours on it. In a short haul today, the SD25 was found to have water ingress to the oil. The... My boat is from 2018 and the propulsion system has 850 hours on it. In a short haul today, the SD25 was found to have water ingress to the oil. The culprit is the shaft seals (not the big diaphragm).

This is seems a short time for these seals to fail. Anyone have a similar experience? ]]> Engines and Propulsion Systems Dr. D https://www.cruisersforum.com/forums/f54/saildrive-shaft-seal-failure-300312.html Universal M35 rebuild https://www.cruisersforum.com/forums/f54/universal-m35-rebuild-300303.html Tue, 19 May 2026 02:46:01 GMT It's a 1995 four cylinder Universal M35/Kubota V1200 diesel motor. It's being taken apart for a change of crankshaft, piston rods bearings, rings etc. After removing gear case cover noticed strange thing on gears. They have markings on teeth for timing of valve shaft, fuel pump shaft, etc. but these markings don't line up as they should. Any ideas why?

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]]> Engines and Propulsion Systems pzmaria https://www.cruisersforum.com/forums/f54/universal-m35-rebuild-300303.html Rebuilding a Yanmar 4JH2-TE for my Ericson https://www.cruisersforum.com/forums/f54/rebuilding-a-yanmar-4jh2-te-for-my-ericson-300299.html Mon, 18 May 2026 22:51:54 GMT I picked up a 4JH2-TE that was pulled from another boat and disassembled after a hurricane gave the exhaust a salt water enima.
It's a bit of a project, but most of the parts are there.

I've just dropped off the block, head and cam with the machine shop.
They are going to tell me: If I need new pistons (and a bore job)
As well as inspect the valves, etc and rebuild the head for me, including a 3 angle valve job if needed. I left the cam so they can polish the lobes - they have some surface rust spots.

Further crazy issues - The guy that pulled the engine disassembled the injection pump (that only had 3000 hours on it), and then put ALLLL of the parts in one damn bag. (not separated by pump cylinder.) I may take over the dining room table and attempt it - I've rebuilt pumps before. But, for my sanity I'm thinking of just buying a rebuilt or a take off.
Beyond that, the turbo is seized with rust, so I'm just hunting down a replacement. That thing is toast.

Overall it'll be a pretty standard engine rebuild, just with bonus missing parts. (like the valve keepers I couldn't find today.)

If you've got advice on where to get decent gasket sets, etc, I'm all ears.
I don't mind buying a yanmar head gasket, but they are asking some crazy $ for piston rings. ]]> Engines and Propulsion Systems WilloCo https://www.cruisersforum.com/forums/f54/rebuilding-a-yanmar-4jh2-te-for-my-ericson-300299.html