Another no start issue!

[Mark101]

Hey guys, after I fixed my last issue at the beginning of the season the boat has run quite well all summer so I'm pleased for that! It's a 1987 mercruiser 260 5.7l. A couple weeks ago I went to start it for our family weekend fishing trip and no start. It's the first time all season it's happened, she usually fires right up! Messing with it for a good part of the day and she turns over but no go so weekend over! The other day I confirmed that fuel is a squirming into the carb and also confirmed that there's no spark! Getting closer now! Looked at cap and rotor and actually looks pretty decent inside. After researching I'm now lead to either an ignition sensor assembly or an oil pressure switch. Ruled out oil switch as it's not fuel injected! So I grabbed an ignition sensor which came with directions for install as it's now a sealed unit but now my problem is that my distributer looks nothing like anything in the instructions. I think it's been changed out in the last. I believe it has points on it which I know nothing about so now I'm at a major roadblock! I think I can buy new points and stuff but I don't even know what or how to order it! I tried to post a pic but for some reason it won't let me! Any help would very much be appreciated!

 

[achris]

1987 was definitely Thunderbolt IV, so if you have points, someone swapped the distributor. You need to check that you have a marine distributor and not some old car unit... That's really important...

Chris...

 

[Mark101]

1987 was definitely Thunderbolt IV, so if you have points, someone swapped the distributor. You need to check that you have a marine distributor and not some old car unit... That's really important...

Chris...

I'm sure someone switched it but how would I know what kind it is?

 

[achris]

A marine distributor doesn't have a vacuum advance unit on the side. A marine cap has a gasket under the surface, and the vent will have a 90° bend in it. A marine cap for a SBC will also be screwed down.

Chris.........

 

[Mark101]

A marine distributor doesn't have a vacuum advance unit on the side. A marine cap has a gasket under the surface, and the vent will have a 90° bend in it. A marine cap for a SBC will also be screwed down.

Chris.........

Well, there's only a little screen on the back of the cap, I assume that's the vent. No gasket and has 2 clips on the side that screw down to hold cap on.
I actually have the bottom housing part in my spare parts bin but no guts unfortunately!
Could there be anything else that would cause a no spark situation? This distributer may not be the right one but it ran fine all summer. I have no problem changing it out but really only want to do that if I can actually diagnose that that's the problem

 

[achris]

If it's points, yeah, dirty/burnt contacts will stop it sparking... Points are notoriously unreliable, and constantly causing exactly the problem you're seeing, works great, then stops for no reason....

I know my next statement will attract philistines who like living in the dark ages (like points and carbs :facepalm, but the best thing you can do it pull that distributor and toss in into the deepest part of the ocean you can find, and install either the original Merc Thunderbolt system, or a AC-Delco Voyager system... Have a read of the installation instructions (available to download form almost any site selling the dizzys) before you start so you know what you're getting yourself into...

Chris....

 

[Scott Danforth]

Chris, its not that we live in the dark ages, its we understand that an electro-mechanical connection can only make about 2 million cycles prior to adjustment and about 100 million cycles prior to wearing out. with the 80 plus times I have been towed, its never been because of points, however 9 times its been failure of electronic ignition.

points are a maintenance item no different than greasing bearings.

file the points you have, gap the points you have and you should get spark. (there is a whole write-up in the stickies) if not, replace them. if you dont want to deal with points, get a delco voyager distributor.

 

[Bt Doctur]

Points are notoriously unreliable, and constantly causing exactly the problem you're seeing, works great, then stops for no reason....

Chris, your wrong. They work perfectly well for atleast 1 year. They do need adjusting from time to time or may need replacement. Most problems are caused by a condensor that went bad., but have worked very well in boats, tractors, aircraft, etc.Dont forget that a bad tach will kill spark too.

To mark, post a pic. It may be a Prestolite dist.

 

[Bt Doctur]

Mark, if you can work a computer and use a screwdriver and a piece of matchbook paper you can install and adjust a points system

 

[Bt Doctur]

 

[Bt Doctur]

 

[alldodge]

Mark post a pic of your distributor

80 plus times I have been towed

Wow

 

[Mark101]

Lots of excellent info here, thanks everyone! I tried to post a pic but it keeps saying file too big and doesn't work! I only have my phone to use as I don't have a computer! Gonna try a different way

 

[Mark101]

 

[Mark101]

 

[alldodge]

Points distributor

I would suggest mark the location of the rotor in reference to where its pointing on the motor. Disassemble the distributor an clean it up, the place back together. Reinstall new points and condenser, and adjust points.

Reinstall distributor with rotor pointing in same location. After all the wires back on, reset timing

 

[Mark101]

Points distributor

I would suggest mark the location of the rotor in reference to where its pointing on the motor. Disassemble the distributor an clean it up, the place back together. Reinstall new points and condenser, and adjust points.

Reinstall distributor with rotor pointing in same location. After all the wires back on, reset timing

I think this is my most viable option! Gonna hit an auto parts store and see if I can get new parts for I'm guessing a late 70's early 80's Chevy 350 motor!

 

[Mark101]

Ok so I have an update! Went to carquest auto parts and explained to the gentleman behind the counter my problem and he was like, looks like a challenge to me! So he went through his parts book and not surprisingly there are a ton of different points systems and by the picture I showed him he started looking for a match, he went to the back bringing out several parts until he came across that seemed to be a decent fit so I grabbed it, along with a condenser that looked similar. Went home and switched out the parts which seemed to fit right away! I set the clearance at 25 thou, not sure if this is the spec but just went with what the old boy said to start at! Hooked up the hose turned the ignition with my fingers and toes crossed and thankfully she fired up straight away without any effort! Man am I glad! Turned out to be a $40 fix which I like way better than the $550 the shop wanted for a new distributor! Really pleased with the parts guy! And certainly couldn't have done it without all the knowledge passed on by the veterans here! Going fishing this weekend! Thanks everyone!!

 

[achris]

Carry spare points, condenser, rotor, cap, timing light and the tools you need to replace them... Also, if you plan on keeping the points system, invest in a dwell meter... Or an advanced timing light, which has all those functions built in.

Chris....

 

[Scott Danforth]

Mark post a pic of your distributor



Wow

Half on water, the other half on land