Help new engine has a miss in the 3800-5000rpm range
06-01-2010 | 04:38 PM
#1
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Joined: Mar 2004
Posts: 1,032
Likes: 1
From: Vermilion, OH
Help new engine has a miss in the 3800-5000rpm range
Any ideas? this is driving me nuts.
This is a new/ rebuilt 547 N/A engine. Has a thunderbolt 4 ignition.
Had it on a dyno and no issues, soon as it went in the boat has miss. Maybe because it was not held in that rpm range it was never noticed on the dyno.
Takes a rev fine.
When im running a constant rpm between 3800 and 5000 you can hear a constant slight miss. 5000-5600 nothing, unless its just not as noticible.
Has a thunderbolt 4 ignition
There is new wires, cap and rotor.
Checked the plugs, they look fine.
Checked all my connections at distributer and coil and module.
Checked rotor and cap and spark plug wire connections.
Im thinking of swapping out coil( thought coils were good or bad) and module next. Then Carb I guess. Fuel pressure is good at idle, not sure when running.
Carb was just rebuilt by engine builder.
This is a new/ rebuilt 547 N/A engine. Has a thunderbolt 4 ignition.
Had it on a dyno and no issues, soon as it went in the boat has miss. Maybe because it was not held in that rpm range it was never noticed on the dyno.
Takes a rev fine.
When im running a constant rpm between 3800 and 5000 you can hear a constant slight miss. 5000-5600 nothing, unless its just not as noticible.
Has a thunderbolt 4 ignition
There is new wires, cap and rotor.
Checked the plugs, they look fine.
Checked all my connections at distributer and coil and module.
Checked rotor and cap and spark plug wire connections.
Im thinking of swapping out coil( thought coils were good or bad) and module next. Then Carb I guess. Fuel pressure is good at idle, not sure when running.
Carb was just rebuilt by engine builder.
06-02-2010 | 09:40 PM
#3
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Joined: Dec 2007
Posts: 784
Likes: 0
From: Detroit River/ lake Erie
Any ideas? this is driving me nuts.
This is a new/ rebuilt 547 N/A engine. Has a thunderbolt 4 ignition.
Had it on a dyno and no issues, soon as it went in the boat has miss. Maybe because it was not held in that rpm range it was never noticed on the dyno.
Takes a rev fine.
When im running a constant rpm between 3800 and 5000 you can hear a constant slight miss. 5000-5600 nothing, unless its just not as noticible.
Has a thunderbolt 4 ignition
There is new wires, cap and rotor.
Checked the plugs, they look fine.
Checked all my connections at distributer and coil and module.
Checked rotor and cap and spark plug wire connections.
Im thinking of swapping out coil( thought coils were good or bad) and module next. Then Carb I guess. Fuel pressure is good at idle, not sure when running.
Carb was just rebuilt by engine builder.
This is a new/ rebuilt 547 N/A engine. Has a thunderbolt 4 ignition.
Had it on a dyno and no issues, soon as it went in the boat has miss. Maybe because it was not held in that rpm range it was never noticed on the dyno.
Takes a rev fine.
When im running a constant rpm between 3800 and 5000 you can hear a constant slight miss. 5000-5600 nothing, unless its just not as noticible.
Has a thunderbolt 4 ignition
There is new wires, cap and rotor.
Checked the plugs, they look fine.
Checked all my connections at distributer and coil and module.
Checked rotor and cap and spark plug wire connections.
Im thinking of swapping out coil( thought coils were good or bad) and module next. Then Carb I guess. Fuel pressure is good at idle, not sure when running.
Carb was just rebuilt by engine builder.
http://www.performancedistributors.com/marinedui.htm
06-02-2010 | 09:44 PM
#4
Registered
Joined: Dec 2007
Posts: 784
Likes: 0
From: Detroit River/ lake Erie
Any ideas? this is driving me nuts.
This is a new/ rebuilt 547 N/A engine. Has a thunderbolt 4 ignition.
Had it on a dyno and no issues, soon as it went in the boat has miss. Maybe because it was not held in that rpm range it was never noticed on the dyno.
Takes a rev fine.
When im running a constant rpm between 3800 and 5000 you can hear a constant slight miss. 5000-5600 nothing, unless its just not as noticible.
Has a thunderbolt 4 ignition
There is new wires, cap and rotor.
Checked the plugs, they look fine.
Checked all my connections at distributer and coil and module.
Checked rotor and cap and spark plug wire connections.
Im thinking of swapping out coil( thought coils were good or bad) and module next. Then Carb I guess. Fuel pressure is good at idle, not sure when running.
Carb was just rebuilt by engine builder.
This is a new/ rebuilt 547 N/A engine. Has a thunderbolt 4 ignition.
Had it on a dyno and no issues, soon as it went in the boat has miss. Maybe because it was not held in that rpm range it was never noticed on the dyno.
Takes a rev fine.
When im running a constant rpm between 3800 and 5000 you can hear a constant slight miss. 5000-5600 nothing, unless its just not as noticible.
Has a thunderbolt 4 ignition
There is new wires, cap and rotor.
Checked the plugs, they look fine.
Checked all my connections at distributer and coil and module.
Checked rotor and cap and spark plug wire connections.
Im thinking of swapping out coil( thought coils were good or bad) and module next. Then Carb I guess. Fuel pressure is good at idle, not sure when running.
Carb was just rebuilt by engine builder.
06-02-2010 | 10:26 PM
#5
Thread Starter
Registered
Joined: Mar 2004
Posts: 1,032
Likes: 1
From: Vermilion, OH
Do you think the hall effect sensor would be fine after 5000rpm though?
06-03-2010 | 07:26 AM
#7
Charter Member
Joined: Jan 2001
Posts: 7,663
Likes: 2
From: Edgerock Baby!!
Also check for distributor shaft play from side to side, will show up as a miss over 3000 rpms.
