3.7 Mercruiser No Spark

[1988regalsebring]

ok i just picked up a cheap boat. first time owning a boat. dont know nothing about them, but i do have my own car shop and what not. well short and simple cranks but no spark. its getting fuel but no spark. took the rotor cap of and it was very ceroded. cleaned it and put it back still no spark. put new plugs in it today didnt do much help. grouded one wire/plug do see if it was getting spark. and no. check everything wires etc. please help or it might just need a new coil. was winterized in 2007 and hasnt been started since then.

 

[stonyloam]

Re: 3.7 Mercruiser No Spark

Three things: points, points, points.

 

[Don S]

Re: 3.7 Mercruiser No Spark

Three things: points, points, points.

You forgot the main cause of no spark Terry, the points!

 

[captk]

Re: 3.7 Mercruiser No Spark

Have you replaced the points?

 

[1988regalsebring]

Re: 3.7 Mercruiser No Spark

i dont know what points are im new to this stuff :/

 

[Miglater]

Re: 3.7 Mercruiser No Spark

points are what was used before pick-up coils were used, it's a mechanical breaker style ignition to collapse the coil field, u may just want to save future headaches and buy the conversion kit as ur not familiar with points/dwell etc...

 

[1988regalsebring]

Re: 3.7 Mercruiser No Spark

i have just found out what points are im about to check.

 

[stonyloam]

Re: 3.7 Mercruiser No Spark

i have just found out what points are im about to check.

Great! You are going to need some stuff, or you can mess things up (if you already have this stuff just ignore me). You must have water flowing to the outdrive before you start the engine, so you will need some muffs to attach a garden hose to for supply. You will have to change the outdrive oil and the waterpump, and do basic outdrive maintenance But first things first, if you do get it to run, run it at low rpm, less than 1500 RPM, and do not let it overheat. If you get that far we can help you with all the other stuff you will need to do to get boating before you take it out. What year boat (guessing 1988 by your name)? If it is that could be a good engine. For tools you will need a dwell meter and timing light, nothing else special yet.

 

[1988regalsebring]

Re: 3.7 Mercruiser No Spark

ok i bought the muffs already but no spark i think im just going to buy the whole new distributer. and see if that will help. or where could i buy the cap locally? the points look worn out.

 

[1988regalsebring]

Re: 3.7 Mercruiser No Spark

Ok got another question whats another way that i can make sure im getting fuel?

 

[Eric 3.7LX Alpha 1]

Re: 3.7 Mercruiser No Spark

ok i bought the muffs already but no spark i think im just going to buy the whole new distributer. and see if that will help. or where could i buy the cap locally? the points look worn out.

Points are something that's replaced on a yearly basis as part of your annual tune up. Replacing the whole dizzy each year will get expensive.

80% of the time the coil is NOT the reason you are not getting spark. There is a test procedure for the coil but I would hold off on it for now

If you go to the Adults Only sticky at the beginning of this forum there is TONS/HOURS of good info which is were these are from:

Read this please it will help you out big time:

How To: Troubleshoot a Points Ignition System
http://forums.iboats.com/showthread.php?t=335407


How To: Tune-up Your Engine with Points Ignition
http://forums.iboats.com/showthread.php?t=335302

Here is your tune up kit for the distributor:
http://www.iboats.com/mall/partfind...gd_poid=355783&gd_row=16&session_id=748000502

 

[Eric 3.7LX Alpha 1]

Re: 3.7 Mercruiser No Spark

Ok got another question whats another way that i can make sure im getting fuel?

In the sticky there is a section on how to test your boat's fuel system.

Thread: ------------ADULTs ONLY -------------------------No Exceptions-----http://forums.iboats.com/showthread.php?t=288430

 

[stonyloam]

Re: 3.7 Mercruiser No Spark

Yeah forget the new distributor, don't waste your money (you will need it elsewhere LOL). Your local NAPA will have the parts, your Mercruiser dealer, or here at i-boats. If you don't like the points, for about $150 you can go with a Petronix conversion. As soon as you get it running you will want to do a compression check and a cooling system pressure check. You can borrow the tools to do both from Autozone. While it is running check the waterpump weep hole, the small hole on the lower sterboard side of the engine waterpump. It must be clear (check with a toothpick) and look to see if antifreeze is leaking out. If it is you will need new cam seals (no big deal).Make sure the reservoir (with the radiator cap) is full of automotive 50/50 antifreeze. When you get it running the next thing you will have to do before you even THINK of taking it to the water is pull the outdrive and check the Bellows, gimbal bearing and U-joints. You will also need to split the outdrive and replace the entire waterpump, impeller and housing. Couple of other things to do in the meantime, check out the trim system and shifting: Trim is easy hop in and hit the trim button on the control handle, down first, should go down until you hear the tone of the motor change, next try trim up, should go up about 1/2 way then stop (if it does not, try thr trailer switch), hit the trailer switch to take it all the way up. The important thing for right now is that the down and trailer work. Never run the engine with the outdrive up. Next thing to check is the shift cable: With the engine not running, push the throttle all the way forward, turn the prop counterclockwise, it should lock, pull back to neutral, prop should spin both ways (may click a little), pull back to reverse, prop should lock when you turn it clockwise (looking at it from behind the boat). If that does not work you probably need a new shift cable. Oh yeah port and starboard, port is the left side of the boat looking from the transom forward, starboard, the right side, and they are always the same, whether looking at the boat from the front or back. Lots of stuff to learn but lots of fun ahead . BTW welcome to the "470 Club" :facepalm:

 

[1988regalsebring]

Re: 3.7 Mercruiser No Spark

ok thetrim will go down but not up. i had to lift it backup on the pump jumping the positive with a wire. i checked the shiftig and all is good. i took the filter of the carb when you move the shifter back and fourth it starts sraying gas into the carb i that normal? thereis no sign of colant leaks it is full of colant in resivorad and lines. sharp boat only has 100 hours. but hen i changed the plugs i noticed they where theoriginal plugs that came in it and wires. nthing on the motor looks like it has never been touched just has been sitting at is house didnt havetime for it. so i bought it.

 

[1988regalsebring]

Re: 3.7 Mercruiser No Spark

and wats something i cn do for old gas? been in there since 2007

 

[1988regalsebring]

Re: 3.7 Mercruiser No Spark

help?

 

[Eric 3.7LX Alpha 1]

Re: 3.7 Mercruiser No Spark

Yeah gas from 07 has to go. Try and siphon it out either thru the normal fuel line into container. They sell a siphon tool to get it going so you don't have to do it the old fashioned way.

You could always get it started off a portable gas can and some hose.

 

[stonyloam]

Re: 3.7 Mercruiser No Spark

ok thetrim will go down but not up. i had to lift it backup on the pump jumping the positive with a wire. i checked the shiftig and all is good. i took the filter of the carb when you move the shifter back and fourth it starts sraying gas into the carb i that normal? thereis no sign of colant leaks it is full of colant in resivorad and lines. sharp boat only has 100 hours. but hen i changed the plugs i noticed they where theoriginal plugs that came in it and wires. nthing on the motor looks like it has never been touched just has been sitting at is house didnt havetime for it. so i bought it.

Cool, making progress! Gas spraying is good. Sounds like the engine is in pretty good shape. When you get the tank emptied, see if you can find some non-ethanol gas to put in it (lots of marinas and some gas stations near boating areas sell it). Sounds like you are on the right track with the engine. Still lots of work to do on the outdrive though. You need to drain the outdrive, remove it from the boat, check and lube the gimbal bearing, grease the universal joints, check the bellows for cracking or leaks, split the outdrive and replace the impeller. Not as bad as it sounds. You do need a Alpha I manual Service Manual #6, someone should be able to give you a link to download it. With your trim, sounds like you have a problem with the trim limit circuit. For now you should be able to use the trailer switch to raise the outdrive. Just make sure it is down when you try to run it.