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91 fountain fever diesel motor?

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Old 06-26-2012, 10:17 AM
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Default 91 fountain fever diesel motor?

I went and looked at a 91 fountain fever the other day it had a merc 502 in it when it was ran it was very noisy.I describe it as a diesel motor sound??? The owner proceded to tell me that this was a normal sound and it has been like this since it was rebuilt (385 hrs ago). Just looking for some imput any would help!!! Has anyone heard some noisy 502s?
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Old 06-26-2012, 06:36 PM
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Depends on what you call noisy.
Mechanical roller cams make more noise than hydraulic cams. EFI makes more ticking and clicking noises than carbs do.

Find out what the motors are (502 Magnum Carb, HP500 Carb, possibly something newer that has been swapped in...). Also find out if they were rebuilt with stock parts or whether they had "upgrades".

502's have forged pistons and run a little more clearance than a cast piston 454, so there is the possibility you'll get a little more piston slap at low revs when cold.

I'm trying hard to think of what is going on and what you are hearing. If it sounds like a Cat 3208, then no, that's not normal at all.

You need to go find another boat with the SAME model of 502's (you didn't say what flavor they were) and listen to it.
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