hot running VP AQ170/270 when gliding

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Dirk
Inlägg: 13
Blev medlem: 09 mar 2017, 21:21

hot running VP AQ170/270 when gliding

Inlägg av Dirk »

Hy guys,
I hope someone can help me with my temperature problem at the port engine AQ170B/270C
Both engines got a complete exhaust clean two year ago. Only running in sweet water, no salt. The starboard engine is running fine in the first 1/3 of the green area. The port engine runs fine with idle speed up to the middle of the green field, but when i run on the sea over 1200 min-1 up to 3200 min-1 the port engine temperature goes up to the beginning of the red level and goes a little bit over it after some minutes. When i go down again to idle speed, some minutes later the temperature goes down to the mid of green field. Sea water pump is ok. Thermostat is ok 55°. Exhaust and elbow is clean. No sea water filter mounted. The temerature of the head is about 80°, exhaust 50°, seawaterpump 25°.After many many test i put off the hose between the transom and the suction tube to the sea water pump and put a long hose on it direct to the sea without the stern drive. I think then it was better, only in the green area. After remount the hose, original to the stern it was also good for one time. One week later the next drive, and the old problem was there again.
Next question: has someone a exactly description of the cooling flow in the engine? in the VP manual is only a rough overview but not exactly explanation in which holes in the exhaust, in the circulation pump, in the thermostat housing, cylinderhead and block the water will flow in which situation. The flow from the stern to the oil cooler is clear but then i am staggering. Perfect would be a description in the warm up phase when the thermostat is closed and after that for the hot second flow cycle.
When the boat (Weekender 24) comes out of the water next month i will change the stern rubbers and unmount the down part of the stern to clean the water flow hose in the stern. Good ideas needed. Thanks for every tip.
Regards
Dirk
Lars Lundbladh
Inlägg: 1499
Blev medlem: 26 jul 2003, 23:46
Ort: Sweden
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Re: hot running VP AQ170/270 when gliding

Inlägg av Lars Lundbladh »

Hi Dirk

It could very well be the cooling water intake hose and the connection to the sterndrive that is corroded, leaking or broken.
See link:
https://drevdelar.se/media/catalog/prod ... 766_1_.jpg

The cooling is quite simple, read more in the workshop manual
https://www.manualslib.com/manual/10037 ... =35#manual

There is also information in the manual for the heat exchanger conversion for the engine.
https://shop.textalk.se/shop/31500/art7 ... 1vp170.pdf


/Lars
Fjord 900 Dolphin -88 /D6
Ordförande och webmaster i Fjordklubben
Dirk
Inlägg: 13
Blev medlem: 09 mar 2017, 21:21

Re: hot running VP AQ170/270 when gliding

Inlägg av Dirk »

Hy Lars,

thanks for the information.
The hose and the hose connector i can check when the boat is out of the water end of the month.
The other sources in will check in the next days.

Best Regards

Dirk
RistoA
Inlägg: 2
Blev medlem: 15 maj 2019, 20:20

Re: hot running VP AQ170/270 when gliding

Inlägg av RistoA »

Hi

I have similar problem with AQ151/290-SP. Checked the hose and the intake adapter, both are fine. Found a leak in drive hinge shaft or shaft seals. Fixing those is a bit more complicated and now I am planning to make new fresh water intake either thru hull or externally to transom.
I made temporary fix outside transom already, but it is such ugly thing bolted under swim deck..

Risto
Lars Lundbladh
Inlägg: 1499
Blev medlem: 26 jul 2003, 23:46
Ort: Sweden
Kontakt:

Re: hot running VP AQ170/270 when gliding

Inlägg av Lars Lundbladh »

I guess that you are referring to the steering shaft. I would say that a small leakage through the steering shaft is almost impossible to cause a flow problem for the cooling water. There are only two sealings involved, the lower o-ring is placed between the lower unit and intermediate house and the other end is a rubber seal placed under the house connector. If the lower o-ring is broken it is not so complicated to fix it. Just separate lower and intermediate housing an change the sealing.

https://www.volvopentashop.com/priordie ... 743320_109

/Lars
Fjord 900 Dolphin -88 /D6
Ordförande och webmaster i Fjordklubben
RistoA
Inlägg: 2
Blev medlem: 15 maj 2019, 20:20

Re: hot running VP AQ170/270 when gliding

Inlägg av RistoA »

Well

We did leak test by blowing air to water intake from within goat and I went to dive and see where air was coming out. It was not coming from hose or connector, but from steering shaft area. I agree, it is very unlikely.
In Finland we have common knowledge, that all AQ 14x, 15x, 17x are overheating easily when old. Based on my limited experience I consider it being intake cooling water problem rather than too small heat exchanger or else design related.

Risto
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