Logo
FULL SITE MENU

1986 crusader port motor help

P

pjdaddo

New member
a little background I bought the boat in 2018 ,the previous owner stated he never ran it over 3000 ,I did the same but was curious to see 4000-4200 and it would misfire ( port) at 3100ish ,and it would run 15-20 deg hotter  (starboard 160) I put 65 hours on the motors that season , last year she didnt go in the water,this year I soaked the port raw side cooling with barnicle buster and it seamed to run sweet I took the boat out saturday she ran nice however I still couldnt get past about 3100 I ran about 3 1/2 hours ,sunday I go out and the port motor starts misfiring at 2200ish so I figured new plugs,wires,cap,rotor ,I replaced the plugs and wires and fired it up , same issue ,I took a video yesterday but I'm having problems loading it here it sounds like a popping or miss fire maybe a clicking sound ,let me know what you guys think ,thanks
 
pjdaddo said:
a little background..... I bought the boat in 2018 , the previous owner stated he never ran it over 3000.
I did the same but was curious to see 4000-4200 and it would misfire ( port) at 3100ish ,and it would run 15-20 deg hotter  (starboard 160)
I put 65 hours on the motors that season.
Last year she didnt go in the water.
This year I soaked the port raw side cooling with barnicle buster and it seamed to run sweet
I took the boat out Saturday she ran nice, however I still couldnt get past about 3100!
I ran about 3 1/2 hours .
Sunday I go out and the port motor starts misfiring at 2200 ish so I figured new plugs, wires, cap, rotor.
I replaced the plugs and wires and fired it up , same issue.
I took a video yesterday but I'm having problems loading it here it sounds like a popping or miss fire maybe a clicking sound.
let me know what you guys think ,thanks
Click to expand...

All marine engine manufacturers will provide what's referred to as a WOT RPM spec.
This is an RPM that the engine should be able to reach (under load) while the throttle is in the full wide open position.

With the hull bottom clean, engine healthy and in full tune, ignition advance as per OEM specs, propeller in full tune, gear reduction correct..... the engine should reach this suggested RPM range.
If not, then something is wrong, and should be corrected before engine damage occurs (if not already too late).


NOTE: WOT RPM is a test RPM, and should not be sustained for any duration.


Suggestions:

...... perform a cylinder pressure test on both engines (aka compression test)... cycle each cylinder through at least 3 compression strokes.
...... if need be, perform a cylinder pressure "leak-down" test.
...... check the ignition advance regarding the progressive and the total advance.
...... since you have twins, swap carburetors to see if the issue follows the carburetor.


Also, what engines are these?

 
RicardoMarine said:
All marine engine manufacturers will provide what's referred to as a WOT RPM spec.
This is an RPM that the engine should be able to reach (under load) while the throttle is in the full wide open position.

With the hull bottom clean, engine healthy and in full tune, ignition advance as per OEM specs, propeller in full tune, gear reduction correct..... the engine should reach this suggested RPM range.
If not, then something is wrong, and should be corrected before engine damage occurs (if not already too late).


NOTE: WOT RPM is a test RPM, and should not be sustained for any duration.


Suggestions:

...... perform a cylinder pressure test on both engines (aka compression test)... cycle each cylinder through at least 3 compression strokes.
...... if need be, perform a cylinder pressure "leak-down" test.
...... check the ignition advance regarding the progressive and the total advance.
...... since you have twins, swap carburetors to see if the issue follows the carburetor.


Also, what engines are these?

the motors are 86 cursadars 350 ci /270hp closed cooling and upgraded to electronic ing
Click to expand...
 
Have you changed the fuel filters yet?

Also, the timing advance mechanism is the factory distributors needs regular maintenance to keep the advance mechanism working properly...and it will be retained if a breakerless kit was installed...
 
makomark said:
Have you changed the fuel filters yet?

Also, the timing advance mechanism is the factory distributors needs regular maintenance to keep the advance mechanism working properly...and it will be retained if a breakerless kit was installed...
Click to expand...

As usual, Mark is leading you in the right direction. If you installed a breaker less ignition plate in the original distributor, take a look at your advance curve. If your getting enough fuel, my bet is the mechanical advance is either locked up (no advance), or a spring broke and you're getting full advance too soon....
Get a timing light and see what/when you're getting in the way of spark advance
 
shock loaded said:
As usual, Mark is leading you in the right direction. If you installed a breaker less ignition plate in the original distributor, take a look at your advance curve. If your getting enough fuel, my bet is the mechanical advance is either locked up (no advance), or a spring broke and you're getting full advance too soon....
Get a timing light and see what/when you're getting in the way of spark advance
Click to expand...

Great advice.

Suggestion:

Mark off your harmonic balancer in increments of 5*, and up to approx 40* from the OEM TDC line.

Use a standard strobe style timing light, and look at the ignition advance as you increase RPM.

Plot this out on graph paper and post it here.


With the known balancer diameter, you can buy a decal that will provide the degrees.
Or...... you can use this simple method to mark your balancer.

timing decal per diameter.jpg
 
Back
Top