Newbie Questions

[Amfan]

Hi all!

New here and new to boats. My son and I bought a used 15 ft fishing boat with a 35 hp Mercury outboard earlier this summer. He's used it 6 or 7 times on the river without any issues, until two weeks ago. The motor basically just quit on him. We found a couple of wires that had burned through, so we fixed those and the motor started up using the hose attachment. Today we tried it again on the river and it died on him. This time he was able to restart it, but was not able to put any throttle into it as it died each time. We are new to marine engines and we do not have the manual for the motor. The serial number is A951675 and I found a site that lists it as a 1986 - can anyone confirm this?

Also, I found what looks like a vacuum hose that looks freshly cut. It is about half way down the shaft of the motor. I do not see another end so I am not sure if this is a problem or not.

Not sure if anyone has any thoughts as to what the issue may be. Thanks.

 

[carholme]

Re: Newbie Questions

Comes up as:

MERCURY - ( 35 H.P. (1986 ))
Serial No: 0A951675 Model No: 1035716

Parts List;

35 H.P. - Mercury, Mercruiser, Force, etc. Parts Lookup

The service manual you require is P/N: 90-42794--1

Some good manual prices here:

Mercury Outboard Service Shop Manual Model 35 40 Boat Repair 90 42794 1 690 | eBay

I think the cut hose you are looking at is the speedometer hose which usually connects to a speedometer gauge on the instrument panel. You will see the hose as item 2 under GEAR HOUSING (DRIVE SHAFT) in the parts list. If you look down the front of the lower unit just about where item 1 is pointing to, you should see a small inlet hole which is for the speedo inlet.

Were you able to identify the wires which burned?

Gerry

 

[TD_Maker]

Re: Newbie Questions

Great job with the new-to-you boat and motor. Some of my best memories are times spent with my son on the water in the earlier days. Working on my motor projects definitely brought us closer together....enjoy yourself! I would give just about anything to fish with my son again, but right now he is serving our country as an Infantry Officer (Army) in Afghanistan. When he gets back, we will fish once again.

The older Mercs (of that generation) did indeed have some wiring issues. Like you found out, rotted wires, or broken wiring is very common....most of these are coming down from the stator or trigger. Look for some bare wiring, or broken insulation, and you may find your culprit.

Carholme has you on the right track. Get a service manual and attack it one step at a time.

 

[Amfan]

Re: Newbie Questions

Thanks for the information guys. I have the service manual on order. I've also looked thru the forum for other helpful information and determined we have a water cooling issue as no water is discharged when the motor is run. Once I get the manual, we will begin to tear it down. Hopefully it is just the impeller or a clogged line.

Once I know what the issue (s) are, I will repost.

Greatly appreciate the information and help.

Tom

 

[Amfan]

Re: Newbie Questions

I received the service manual in the mail this week. So my son and I started to tear down the mercury. Following the directions in the manual we were able to get the lower unit off without much issue. Once I removed the water pump cover we found that the impeller had seen better days. Hopefully we'll find a rebuild kit (impeller, gaskets) locally and that this is the source of our issue.

Getting back to my earlier post when I mentioned there were a couple wires that were burned. In the attached pic the green w/yellow stripe and the black wires were the victims. I separated them, wrapped them in electrical tape and placed the loom around them which helps keep them off the top of the engine.

Thanks for the help and guidance.

Tom

 

[carholme]

Re: Newbie Questions

Tom;

Is this a tiller, manual start, electric start, remote controls setup?

The green/yellow wire should be the wire from the switchbox to the #1 coil and the black is ground.

I don't know which manual you have but if you are having problems with the wiring diagrams, I can send them to you if you PM me with an email address.

Gerry

 

[Amfan]

Re: Newbie Questions

From a wiring perspective I think we are fine. Once we got them separated, taped and in the loom things have been ok.

***Edit*** Forgot to mention - we have electric start and remote controls.

Over the weekend we attempted to replace the impeller with the rebuild kit that we got from the a local marina shop. The replacement parts seemed to go in without issues. Before reinstalling the lower unit we noticed that the copper water pipe was not attached to the power head. So we figured out how to remove the power head and reattach the pipe. Put everything back together.......setup the ear muffs and the water hose.........started it..........no water out the tell-tale. Took the lower end off again and saw that we shredded the impeller again.

Got a second impeller and had the marina tech check out our installation which seemed to be ok. This time we started the motor up and had water coming out the tell tale. Yeah!

Then we noticed that water was gushing out around the top spark plug. Seems that the gasket is shop. So our boat and engine are at the marina shop to have that gasket changed. They said it should be ready by the end of the week as they are knee deep into winterizing work right now.

Hopefully this is the last issue we have to deal with.

Thanks

Tom

 

[Amfan]

Re: Newbie Questions

Latest update: The marina called late yesterday to say that the repairs have been made. They noted that the engine was over heated as they found aluminum on the top spark plug and the water jacket gasket was cooked. They performed a compression test and found that it is still within specs, but I will be retesting it once we get it home. So we may have dodged a bullet. Going to pick up the boat this afternoon. They recommended that we increase the oil to gas ratio in an effort to free up any of the rings that may have started to freeze. Hopefully the weather holds up this weekend and we can take it out on the river to test things out.

Thanks for all the help.

Tom