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1983 305 No top end power over 3000 rpm 500 hrs

J

jfennell55us

New member
Hi

I have 83 carver mariner with 305's engines have about 500 hours on them. One of the engines will not go over 3000 rpms. I have put new plugs, wires, cap, rotors, points and condenser. I set the dwell and timing. I took the carb apart and dipped it to clean it out put new gaskets and float. I also made sure I have no water in my tanks. Just seeing if anyone else has had this issue.

Thanks
 
My question would be what changed when you started having this problem? was it after a tune up? Are you running both engines on the same tank? Also have you changed out your fuel filters? What shape are your fuel lines in? Find what changed and that will hopefully get you to the problem so you can solve it.
 
These chevy small block engines will run pretty smooth, even with a crossed spark plug wire, just not deliver full power. But not just any crossed wire, it's only a certain combination of two wires? Otherwise, it would be very noticeable. Check your spark plug wiring, Right side cylinders from front 1-3-5, Left side cylinders from front 2-4-6. Firing order: 1-6-5-4-3-2 clockwise rotation.
 
Assuming you did the work identified correctly, and the problem persists, I'd check the "other" timing function.

The ignition needs to advance correctly for the engine to produce max output and inability to achieve WOT is one symptom of a frozen advance mechanism.

The other item to verify is adequate fuel supply to the carb (and fresh fuel too) - if the bowl runs dry (or very low), WOT will never happen....could be a dirty filter/screen....could be the mechanical pump is worn...switching tanks, if your plumbing allows, may yield some insight.
 
MikDee said:
These chevy small block engines will run pretty smooth, even with a crossed spark plug wire, just not deliver full power. But not just any crossed wire, it's only a certain combination of two wires? Otherwise, it would be very noticeable. Check your spark plug wiring, Right side cylinders from front 1-3-5, Left side cylinders from front 2-4-6. Firing order: 1-6-5-4-3-2 clockwise rotation.
Click to expand...

Oops! Sorry, this is the firing order for a Chevy 4.3 V6! The 305/5.0 motor, and the 350/5.7 motor firing order is the same: Front
right side 1-3-5-7, Front left side 2-4-6-8 Rotation clockwise 1-8-4-3-6-5-7-2 I only say this, because I had this happen to me.

A vandal got under the hood of my car, and switched 2 plug wires ( I think it was # 6, and #8,) on the passenger side of my car at the railroad station parking lot, while I was at work in the city, just to screw with me. When I got back to the car, (a 72' Camaro SS), & started it, it sounded different? But ran good, not full power! When I got home a few miles away, I checked the wiring, found the issue, and fixed it. If I didn't have a mechanics ear, & some mechanical skills, I'd have never known what the problem was? The engine ran smooth as silk, but had no power!
 
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ok thanks i will check this stuff out and let you know what i find out. I just installed a new fuel pump because the one that was on there was the original one. Boat goes in on the 10th so we will see what happens. Thanks again
 
jfennell55us said:
Hi

I have 83 carver mariner with 305's engines have about 500 hours on them. One of the engines will not go over 3000 rpms. I have put new plugs, wires, cap, rotors, points and condenser. I set the dwell and timing. I took the carb apart and dipped it to clean it out put new gaskets and float. I also made sure I have no water in my tanks. Just seeing if anyone else has had this issue.

Thanks
Click to expand...

Setting dwell is good, but it will not account for any 30 year old ignition distributor shaft wobble.
Make certain that your shafts do not offer any excessive clearance.
Any shaft wobble may create an errattic dwell, of which will cause issues.

As per Mark's suggestion.... post #5...., when you set the ignition advance.... did you check to see what the progressive and total advance were doing??? If not advancing correctly, performance will be very poor.
Set BASE advance.... but always check the progressive and TA.


May I assume that you have both a RH and LH rotation engine???
(see image below)

For the Reverse RH engine, we check the progressive advance and total advance just as we do with the Std LH engine.... but we will be stobing the harmonic balancer in the oposite direction.

The ignition advance specs for the RH engine will be very similar to the Std LH engine....., if not the same.
(see image for example)
 

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We think we got it figured out there was a couple of problemes. The top door on the carb for the big barrels in the back was only opening about 1/4 of the way we adjusted the tension on the door and now it is working good. We also checked the timing advance and it was over advancing alot I pulled both of the distributors and took them apart found that the springs on the advance weights were very rusted and worn out. Took me three days of searching to find the new springs for a prestolite distributor the only place i could find them was http://www.lakelandautomarine.com/ if any one is ever in need. I did a ton of looking around it seems like its a very common issue on crusader 220's with prestolites every post i found said motors would not go over 3200 rpms. I am going to put them in this week so we will see how it goes.

I attached a pic of the inside of the distributor under the breaker plate.
 
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