merc 260 tune-up

[boatman37]

started my tune-up tonight but it got dark. got all the plugs changed in the starboard side but then it got dark. going down in the morning to finish it up. but i pulled my coil wire off and the plug well had a bunch of liquid in it. looked like water but i'm assuming it was oil? its a 1986 merc 260 thunderbolt IV. the engine was running pretty good but seemed to have a slight miss and would only rev to about 3800 RPM. idle was pretty low but i attributed that to the misfire.

any thoughts on this coil? i can test it tomorrow but may just replace it either way. any idea what i should tell auto-zone this is for? i got the wires for a 1986 caprice but wasn't thinking. it didn't come with a coil wire. so need to find a new coil wire now too.

BTW-i bought AC MR43TS. same thing that was just in it.

on another note, i was going to remove the dist. cap but could only get 3 of the 4 screws loose. grabbed a few better screwdrivers to take tomorrow that hopefully have better grip. may try spraying with PB Blaster but don't want to get any inside the dist. anyone ever ran into this?

the reason i'm doing this now is to see how the WOT RPM is to see if i need to change props in the off season. i can hit about 34 mph at 3800 rpm with a 14.5x17 3 blade. sea ray calls for a 15x15 on it. i'd like to get a little quicker plane. not concerned with top speed. i can cruise and hold plane at about 24 mph. but we can address that after the tune-up is done and i see where we are at then

 

[flipbro]

Don't forget to change water\fuel filter!

 

[boatman37]

yeah. have to get that later this week at the boat shop. looking at a coil for a 1970 chevelle 350 and it shows a min 1.5 ohm primary and 11,000 secondary. the merc manual says i need .6-,8 primary and 9400-11,700 on the secondary

 

[Bondo]

looking at a coil for a 1970 chevelle 350

Ayuh,.... Chevy never used the T-Bolt ignition,.... Mercruiser does though,.....

 

[boatman37]

yeah...finding out not all coils are the same...lol. closest i found was an Accel 8145 but nobody around here has one in stock.

 

[alldodge]

Here is the Sierra coil
http://www.iboats.com/mall/partfind...gd_poid=111750&gd_row=63&session_id=728531104

Now if you want Merc google the part number 300-8M0079202

 

[boatman37]

thanks AD. was hoping to find one today so i could finish this up. maybe one of the guys at the marina will have a spare i could try. supposed to get hit pretty hard with rain this afternoon. not sure how many more decent weekends we have left

 

[Bondo]

Ayuh,.... Check the garbage cans,....

Hundreds upon thousands of perfectly good ignition coils are thrown away every year, because it's "Easy" to change when a motor won't start,....

 

[boatman37]

dumpster divin'!!!

 

[boatman37]

replaced the cap, rotor, wires, and plugs. took it out for a test. max RPM was 4000 and about 34.5 mph (gps verified). i could only get 3800 rpm before but still low. i still need to change the fuel filter and coil. i checked mine today. the primaries were 0.00 resistance and the secondary was 10.50. but i had the battery switch turned off but all connections still connected. why 0.00 on the primary? would it even run?

any idea what fuel filter in need for in the carb? engine S/N is 0A593759

 

[alldodge]

replaced the cap, rotor, wires, and plugs. took it out for a test. max RPM was 4000 and about 34.5 mph (gps verified). i could only get 3800 rpm before but still low. i still need to change the fuel filter and coil. i checked mine today. the primaries were 0.00 resistance and the secondary was 10.50. but i had the battery switch turned off but all connections still connected. why 0.00 on the primary? would it even run?

With the wires still connected is the reason your seeing your low readings

any idea what fuel filter in need for in the carb? engine S/N is 0A593759

Yours will either be a 1 inch or 2 inch long filter. The Merc site shows the item but nut the part number. Remove fuel line and housing and have a look would be the easiest.

Once you know the length just google Rochester fuel filter

 

[boatman37]

will do. likely won't be near the boat for 2 more weeks. have plans all next weekend. thanks