Hi, I recently bought an O'Day 28, 1983 model, with an Atomic 4 diesel engine. The engine is cooled with raw water intake and has been in salt water all its life. The cooling system seems to work fine, but the head has never been pulled so the cooling system could be checked for leaks. Do I have anything to worry about? Should I have the system checked?
- Status
What??????
To my knowledge, the A-4 is a gasoline engine. The thhing is near indestructable, It might run on diesel, but it will work way better with gas. If it is indeed a gas engine let me know and I might be able to help Fair Winds Cap'n Dave
To my knowledge, the A-4 is a gasoline engine. The thhing is near indestructable, It might run on diesel, but it will work way better with gas. If it is indeed a gas engine let me know and I might be able to help Fair Winds Cap'n Dave
A4 diesels
The A4 gas engine was quite popular but there are/were indeed various A4 diesels, the 5411, 5416 and 5424 models being three made by Universal. If it were mine and appeared to be running properly at the proper temperature, I wouldn't worry too much about the raw water colling system until it starts to give yo problems. I had one for years and only had to replace the exhaust elbow once.
The A4 gas engine was quite popular but there are/were indeed various A4 diesels, the 5411, 5416 and 5424 models being three made by Universal. If it were mine and appeared to be running properly at the proper temperature, I wouldn't worry too much about the raw water colling system until it starts to give yo problems. I had one for years and only had to replace the exhaust elbow once.
Thanks Mick
As you pointed out an A-4 is a gas engine made by Universal. Universal did make marine diesel engines using the Kubota engine. None of the latter are Atomic 4's. I will concede the engines were called Atomic Diesels by Universal but none were called Atomic 4. Atomic 4 is a model designation. The only 4 cylinder diesel was the Atomic 5432. The only model that was sea water cooled was the Atomic 5411 There are diesel engines made today designed to replace the Atomic 4, they have the same footprint, but alas Don they are not Atomic 4's So back to the original question. What engine does he really have? Fair Winds Cap'n Dave
As you pointed out an A-4 is a gas engine made by Universal. Universal did make marine diesel engines using the Kubota engine. None of the latter are Atomic 4's. I will concede the engines were called Atomic Diesels by Universal but none were called Atomic 4. Atomic 4 is a model designation. The only 4 cylinder diesel was the Atomic 5432. The only model that was sea water cooled was the Atomic 5411 There are diesel engines made today designed to replace the Atomic 4, they have the same footprint, but alas Don they are not Atomic 4's So back to the original question. What engine does he really have? Fair Winds Cap'n Dave
The 'best' maintenance for a raw water cooled A4 is ......
The following applies to both the gasoline Atomic 4 and the Universal Diesel. Be sure the thermostat is for 'raw' water cooling, one that fully CLOSES at 135 degrees (the Atomic 4 is a BYPASS thermostat system ... thus works 'backwards' than the normal automotive T-'stat' .... Im not sure the configuration of the Universal Diesel). A 'normal' T-stat will be for 180 degrees F. and at that temperature the cooling water will more rapidly foul the engine with scale. Anytime saltwater or 'raw' water goes above ~145 degrees F. the carbonates in the water will start to 'precipitate' and form scale inside the engine. For raw water cooling A4 or any raw water cooled diesel, its best to 'descale' the engine AND the exhaust manifold with a commercial boiler descaler to remove the built-up carbonates internal to the engine and the exhaust manifold. Do this at the first sign of overheating or at least every 2 years. Suitable descaling compounds are "RydLyme" or "Marsolve". Such compounds are 'inhibited' and wont dissolve the engine's base metal; plus, they can be 'dumped overboard' as they rapidly decompose/dilute and wont harm the environment, etc. Dont use muriatic acid, etc. to 'pickle' an A4 .... you'll dissolve 'metal'. On a raw water cooled engine, it best to monitor with an Infrared 'distance' thermometer. Record the IR temperature reading on various places along the cooling circuit. When you note a significant thermal rise from one spot .... time to 'descale'. Example of a 'distance' IR thermometer (pyrometer): www.amazon.com/KINTREX-Clear-Temp-IRT0421-Non-Contact/dp/B0017L9Q9C/ref=pd_bbs_sr_5?ie=UTF8&s=home-garden&qid=1213332469&sr=8-5 FWIW: The exhaust manifold on the A4 and most Univeral Diesels is subject to "Slab Rust". Large Plates of Rust may break off of the internal casting of the manifold and partly or fully block the water passage of the manifold. Best means to prevent 'slab rust' is to **run the hell out of the engine** every so often; and, NEVER drain the engine/manifold and long term store the engine 'dry'. Always for long term storage (months) is to fill the engine and exhaust manifold with a 50:50 mix of antifreeze and water. Buy 'good' antifreeze; that which also contains anti-rust compounds. hope this helps
The following applies to both the gasoline Atomic 4 and the Universal Diesel. Be sure the thermostat is for 'raw' water cooling, one that fully CLOSES at 135 degrees (the Atomic 4 is a BYPASS thermostat system ... thus works 'backwards' than the normal automotive T-'stat' .... Im not sure the configuration of the Universal Diesel). A 'normal' T-stat will be for 180 degrees F. and at that temperature the cooling water will more rapidly foul the engine with scale. Anytime saltwater or 'raw' water goes above ~145 degrees F. the carbonates in the water will start to 'precipitate' and form scale inside the engine. For raw water cooling A4 or any raw water cooled diesel, its best to 'descale' the engine AND the exhaust manifold with a commercial boiler descaler to remove the built-up carbonates internal to the engine and the exhaust manifold. Do this at the first sign of overheating or at least every 2 years. Suitable descaling compounds are "RydLyme" or "Marsolve". Such compounds are 'inhibited' and wont dissolve the engine's base metal; plus, they can be 'dumped overboard' as they rapidly decompose/dilute and wont harm the environment, etc. Dont use muriatic acid, etc. to 'pickle' an A4 .... you'll dissolve 'metal'. On a raw water cooled engine, it best to monitor with an Infrared 'distance' thermometer. Record the IR temperature reading on various places along the cooling circuit. When you note a significant thermal rise from one spot .... time to 'descale'. Example of a 'distance' IR thermometer (pyrometer): www.amazon.com/KINTREX-Clear-Temp-IRT0421-Non-Contact/dp/B0017L9Q9C/ref=pd_bbs_sr_5?ie=UTF8&s=home-garden&qid=1213332469&sr=8-5 FWIW: The exhaust manifold on the A4 and most Univeral Diesels is subject to "Slab Rust". Large Plates of Rust may break off of the internal casting of the manifold and partly or fully block the water passage of the manifold. Best means to prevent 'slab rust' is to **run the hell out of the engine** every so often; and, NEVER drain the engine/manifold and long term store the engine 'dry'. Always for long term storage (months) is to fill the engine and exhaust manifold with a 50:50 mix of antifreeze and water. Buy 'good' antifreeze; that which also contains anti-rust compounds. hope this helps
- Status