496 HO Falls flat on its face under load.

mepilotunot

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Jan 14, 2017
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Just acquired a Chris Craft 252 with a 496 ho/ Bravo 3 swap. According previous owner the engine would idle and start fine. Once placed into gear it would fall on its face and claim to have lost fuel pressure (not sure how he learned this yet). He seems to think the high pressure pump needs to be replaced. I'm not familiar with the 496 HO as of yet. I will start the trouble shoot soon. Any ideas where to start.
 

alldodge

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Mar 8, 2009
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Howdy

How about a engine serial number?

How long have you had the boat?
Did you take it for a test drive?
Have the fuel filters been replaced?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Have you checked the fuel pressure?

Filters?
 

mxcobra

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my engine isn't evan close to yours, except for v8 and mercruiser. Mine is much older and smaller ,that being said. this last summer it started up with those same symptoms . Mine was just plain wore out and needed a long block replacement or rebuild.
 

mepilotunot

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Jan 14, 2017
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My friend and I were on the lake when we smoked the old motor ( small block ford)few years back. He opted to purchase this 496 to swap it in. He also purchased a Bravo 3 drive. He had like 15G into the swap. He had a falling out with the shop that installed it like many to include myself. This shop has been going downhill since the son took over. I had moved out of town so I was not there to oversee the swap. My friend is not a mechanic and just pretty much paid the bill. At this point my friend has had enough and just handed me the paperwork and said I'm done and its yours for the cost of this years storage fee. The boat is spotless and well cared for so its worth the time to try and get it sorted. I have the tools and equip to trouble shoot and pull motor if needed. I have rebuilt my older mercruisers in the past so I'm not scared to get into it. This is my first fuel injected set up and I do not have a scan tool. I will pull serial numbers once its here at the shop. Getting my trailer out of a snow bank today and going to set it up for the 252 Chris Craft.
​No idea on fuel filter...I will put new in just for the simple fact its been sitting winterized since 2015.
​Fuel pressure drops under load is all he told me.
 

alldodge

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Fuel pressure drops under load is all he told me.

This is a good place to start. The motor can have one of two fuel systems depending on the serial number. Will have cool fuel module mounted under the port motor mount with a boost pump on the starboard side above the filter. Or it will have a fuel box on the starboard side which contains both fuel pumps and fuel filter.
 
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