NTA 855 engine “hunting”

[Matthew]

Hello guys.

Does anybody has experience with those engines? I did replace today PT pump,from reason that engine was “hunting”,not much,but engineer was complaining about it.

This happenes when engine is warmer,and did check fuel system,hoses,filters,all seems good.

Looking for some advice regarding it,so that i can explore more about it,thank you.

Topic

[Matthew]

Pump was replaced because engineer was sudgesting to change it,they did have new one onboard.

But problem is still there also with new pump a’m affraid. Will send you few photos of that oump,it is also “new” engine for me,didn’t see them till now in pleasure yachts.

[Tony Athens]

Picture– You need to send me good pics of your pump.. It’s been 10++++ years since I have had one of these engines in my shop.

So, did this all start after a pump “replacement” ?

Why was the pump replaced?

[Matthew]

Hello Tony. I did install new pump. Can you show me on that photo which fitting you mean?

[Tony Athens]

PT Pump Hunting

Sorry for the delayed response.

1) Remove the 90 Degree ( or straight) inlet fitting to the pump–Replace the O-ring /washer- reassemble with a light cost of RectorSeal #5–Most likely place of suck air.

2) If that does not fix it, then put both the inlet hose and the return hose in a clean bucket with clear fuel in it.. Run the engine and look for air ( actually combustion air) from one (or more ) injectors leaking across the copper seal washer to the return line.

[Matthew]

Hello Tony,yes,it that type of pump,exactly.

[Tony Athens]

Does you “pump” look like this?

[Author]

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