1987 Omc 5.7 (chevy 350) timing procedure

[foilled]

The harmonic balancer has multiple numbers as well as the timing tab. The timing tab had 8 highlighted. Do i match 8 to 8 on the harmonic balancer to the 8 on the tab or is it 0 to 8? Or 8 to 0?

 

[Maclin]

Advance until the balancer line, or Zero, is at the 8 on the tab. That is, if you are looking at a target of 8 degrees btdc

 

[Lou C]

You are looking to align the single line across the harmonic balancer with the notch on the timing tab that corresponds with 8* BTDC. Keep in mind you should:
first check and adjust dwell because dwell affects timing
make sure your idle speed is correct (600 rpm) because you don't want any spark advance happening when you set base timing. If you have the OE distributor it should be a Prestolite points distributor with centrifugal advance.

 

[foilled]

You are looking to align the single line across the harmonic balancer with the notch on the timing tab that corresponds with 8* BTDC. Keep in mind you should:
first check and adjust dwell because dwell affects timing
make sure your idle speed is correct (600 rpm) because you don't want any spark advance happening when you set base timing. If you have the OE distributor it should be a Prestolite points distributor with centrifugal advance.

How do i check the dwell, and is there a way to verify my rpm is reading correctly? I dont have a tach.

 

[Scott Danforth]

How do i check the dwell, and is there a way to verify my rpm is reading correctly? I dont have a tach.

you borrow a dwell meter and a tach then.

they loan those tools at Autozone

 

[foilled]

you borrow a dwell meter and a tach then.

they loan those tools at Autozone

Just called napa autozone and advanced auto. All said they dont loan them. Would i be okay just checking timing to verify and if even if its off just a little bit change it back to oem setting. Theres no actually problems im trying to fix . I just rebuilt the carburator and im about to tune it. Just wanted to check ignition system with timing. I already have to buy timing light to check and didnt want to have to get a dwell meter and tachometer aswell. (Been relying on dash gauge for idle rpm.) When i bought boat originally idle rpm was in range and WOT rpm was also in range so i was hoping its accurate. And after carb tune i set it back to same 600rpm at idle and it seems to operate and shift smoothly.

 

[kenny nunez]

To get rid of the dwell setting procedure just convert the distributor to a Petronics Electronic kit.

 

[Scott Danforth]

Either perform the maintenance correctly or pay someone to do it.

There are no shortcuts

 

[Lou C]

Please don't take this the wrong way but anyone trying to 'tune' an old school engine without a tach/dwell meter and a timing light, ahh....you're not really serious about doing it the right way. Do it right or pay to get it done.

I got my first tach/dwell meter and a timing light....in 1975...doing my family's and friends' cars....come on, the tools are not expensive...compared to ruining your engine doing it wrong/

 

[foilled]

Please don't take this the wrong way but anyone trying to 'tune' an old school engine without a tach/dwell meter and a timing light, ahh....you're not really serious about doing it the right way. Do it right or pay to get it done.

I got my first tach/dwell meter and a timing light....in 1975...doing my family's and friends' cars....come on, the tools are not expensive...compared to ruining your engine doing it wrong/

Okay ill do it the right way, ill have to order parts but planned on going out this weeked. Would a trip this weekend by fine i checked timing beforehand its at 4 degrees while manual says 8 degrees or fix it immediately before any boat driving?

 

[foilled]

Either perform the maintenance correctly or pay someone to do it.

There are no shortcuts

Okay ill do it right just need to get tools in. Whats your opinion on if a trip this weekend is safe while waiting to complete maintaince. Its at 4 degrees i need 8 degrees?

 

[foilled]

Heres a photo of under my distributor. How do i set the dwell angle? Is the point gap set aready after i set dwell angle or is that separate? After dwells set do timing right? Do i just hook up tool and read timing and turn distributor as needed or do i need to unplug or block anything on distributor before hand? Thanks

 

[foilled]

Please don't take this the wrong way but anyone trying to 'tune' an old school engine without a tach/dwell meter and a timing light, ahh....you're not really serious about doing it the right way. Do it right or pay to get it done.

I got my first tach/dwell meter and a timing light....in 1975...doing my family's and friends' cars....come on, the tools are not expensive...compared to ruining your engine doing it wrong/

Actually turns out manual says 5 degress for 86 octane. Engine is not same as when manual came with it, being it was rebuilt by Jasper. Theres a white mark on both the timing tab and pulley. 8 degrees on tab is marked. Im currently at 4 degrees. Should i not move it, set to manual spec or should i do 8 degrees which is clearly marked on timing tab??

 

[Scott Danforth]

Okay ill do it right just need to get tools in. Whats your opinion on if a trip this weekend is safe while waiting to complete maintaince. Its at 4 degrees i need 8 degrees?

if your dwell is correct, and your just at 4 degrees, then your simply down on power

Heres a photo of under my distributor. How do i set the dwell angle? Is the point gap set aready after i set dwell angle or is that separate? After dwells set do timing right? Do i just hook up tool and read timing and turn distributor as needed or do i need to unplug or block anything on distributor before hand? Thanks

you hook the dwell meter up to verify the dwell. adjusting the gap is what adjusts the dwell. if you didnt file the points, you didnt really set the gap

I normally read/adjust while cranking with the cap off and plugs out. however thats me. been doing it for 40 years that way

however your pic shows that you have an electronic conversion done, so you no longer have points and the dwell is fixed. you only need to set the timing

read links 17, 18, 19 for further understanding of points https://forums.iboats.com/forum/engi...ion-for-diyers

 

[foilled]

if your dwell is correct, and your just at 4 degrees, then your simply down on power



you hook the dwell meter up to verify the dwell. adjusting the gap is what adjusts the dwell. if you didnt file the points, you didnt really set the gap

I normally read/adjust while cranking with the cap off and plugs out. however thats me. been doing it for 40 years that way

however your pic shows that you have an electronic conversion done, so you no longer have points and the dwell is fixed. you only need to set the timing

read links 17, 18, 19 for further understanding of points https://forums.iboats.com/forum/engi...ion-for-diyers

Sounds good. Do i take any additional steps when so timing or do i just hook it up and turn distributor? Alsoim trying to figuer out what timing to set it at. Manual says 5 degrees im at 4 but theres a white mark on 8 degrees. im thinking 8 degreees. I called jasper and they said they dont set it when they rebuild it that would be the shop they send it to but the marine tech said 8 to 10 degrees. So probably just set at 8, what do you think?

 

[Scott Danforth]

hook up and adjust dizzy

8 BTDC is fine for 87 octane

 

[Lou C]

8 is fine and yeah you don't have to worry about dwell, that Mallory is doing it for you. Now one question, were the changes made to make the OMC ESA work with the electronic ignition? Normally you'd have to use a different ESA module or wire it like a Merc Alpha. Before you put this boat in the water, trigger the load lever on the shift linkage which will activate the interrupt switch, the engine RPM should lower from about 600 down to 450 or so (it will seem like its barely running). If this does stumble the engine, then you have to deal with this or you may not be able to shift your Cobra drive from in-gear to neutral while on the water.

 

[Lou C]

Here is a pic, when you move this load lever with the engine idling lets say at 600, it should noticeably lower the idle speed, on mine it lowers it to about 450 rpm. Now on the water hose, this will not engage because there is no load on the shift cable but in the water there is and you will have trouble shifting into neutral if it does not function as I described.

 

[foilled]

8 is fine and yeah you don't have to worry about dwell, that Mallory is doing it for you. Now one question, were the changes made to make the OMC ESA work with the electronic ignition? Normally you'd have to use a different ESA module or wire it like a Merc Alpha. Before you put this boat in the water, trigger the load lever on the shift linkage which will activate the interrupt switch, the engine RPM should lower from about 600 down to 450 or so (it will seem like its barely running). If this does stumble the engine, then you have to deal with this or you may not be able to shift your Cobra drive from in-gear to neutral while on the water.

Yes esa must be set up as I’ve pushed it in and engine did stumble although boat shifting into and out of gear smoothly with no issues