3.7L Merc cranks but will not start - Please Help!!!!

[NoGin]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

Crappy all day so I didn't get a chance to work on the boat.

Does coolant run through the hose from the stern drive or only seawater?

 

[Maclin]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

If you mean coolant is coming out of the idle relief ports at the bottom of the transom, then removing the transom plate will not fix that. Sounds like you have a bad heat exchanger to me, letting coolant mix in with the exiting raw water.

 

[NoGin]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

Thanks for the reply. I started a new thread here for this issue.

http://forums.iboats.com/showthread.php?t=316994

Thanks again!

 

[NoGin]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

Now she wouln't turn over. Cranks all day, but will not start ? ? ? ? ?

 

[NoGin]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

Any insight fellers? DON S - Can you please expand on "your wiring is all screwed up." ? ?

 

[NoGin]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

Will be on the boat all day today.

Need to get her running. If she cranks well but does not turn over ... ???

Coil?
Distributor?
Plugs?
Wires?
Kill Switch?
Shift Cable Adjustment?

anything else ???

Please help me ASAP as I will be headed to the boat soon.

Thanks.

 

[Bob_VT]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

I have been following your posts. You have invested in the boat with not only money but time and frustration. This is just my opinion but ..... I would hire a marine tech to come and take a sincere look. The tech needs to be someone who is familiar with 3.7 set up.

With your coolant leak .... it may be a blessing that it has not started. If your manifolds are leaking..... you will get water/coolant into the cylinders which will prevent starting.

My personal diagnosis route on a 3.7

Visual inspection for broken wires, cracks, leaks

Check fluids Anti freeze, oil, and gasoline filter seperator

Check coil, distributor, spark plug wires and spark plugs do you have points or electronic ignition....... seriously if you are not sure.... go get marine tech help.

I would crank the motor without the plugs installed and the coil wire removed and check for indications of water or coolant in all four cylinders.

I would check the carb and make sure it is pumping fuel...... then check /re-install the plugs.

The weather has been ugly and if you have been working alone on all this it is worse. Even at last resort get a friend so there is another set of eyes.

 

[NoGin]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

Thanks for the advice Bob_VT. Yes the weather has been and is horrible and I am going about this on my own. Very difficult situation for me. I have reached out to a few local boat techs but it seems they are all too busy to make the trip to my house to see the boat.

At this point I am very frustrated and really on the verge of giving up. I am a first time boater with limited funds and knowledge (but am learning quickly). That is why I lean on the forum members for help/advice which has been minimal to say the least.

Thanks again for your advice.

~ Previous owner said he upgraded to electronic ignition. How do I check for this?

 

[Bob_VT]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

Electronic ignition will NOT have points inside the distributor.

 

[NoGin]

Re: 3.7L Merc cranks but will not start - Please Help!!!!

We got the engine to start however just after cranking it a few times and releasing the key. It only caught when the key was released. We finally figured it out yesterday and I nor my mechanic have never seen this before.

The started grounding cable to the block was so corroded it it was limiting the current. We cut a good 18 inches off and it was still corroded! We replaced the cable and she starts on the first try every time.