1968 Mercury Outboard 35HP Twin

Hello, I'm new to this forum and rather new boater. I have had boats before but had work done by professionals. I have an Old Town Wooden Boat (1950's) with a 35 HP Merc Outboard. When purchased, I replaced all the wiring (internal and external harness), resoldered all the contacts in the Mercontrol, changed points, plugs and gapped per manuel. I changed gas hoses, put a new gas pump kit in and took the carberator off and soaked all the crud off and reassembled. New gas and oil mix put in the tank. NOW::: I sprayed a little starter fluid into the carb and got it to start then stalled. Repeated about 10 times with same results. Then POW! the darn thing ran. I adjusted the high and low on the carb and have the thing purring like a kitten (45 year old kitten). Problem is the next day (cold engine), I have to go through the same procedure with many stalls. I don't have a plug spark tester but I started the motor at night and removed the plugs from engine and cranked a little and saw a very nice blue spark from both plugs. I don't think its the plugs because once the motor warms up it runs fine. What am I missing for an easier start-up. Thank You. Dave J

Re: 1968 Mercury Outboard 35HP Twin

First , never use starting fluid on a 2 stroke outboard. Use fuel mixture for the motor in a spray bottle for hard starting motors. Now for the cold start troubles. It sounds as tho that the compleate fuel system needs to be looked at and repaired as needed, Rebuild carb, replace fuel hoses, rebuild fuel pump, and replace fuel line and or primer bulb and any fuel filters. Check the timming and link and sync of the motor and carb. A manual for the motor can and should be bought if you do not have one. One can sometimes be for sale on Ebay or a call to Merc Marine might get you one or a place where on can be bought. JMO
Oldman570

Re: 1968 Mercury Outboard 35HP Twin

Thank You oldman570. What is the reason not to use starting fluid on 2 cycles? Can says safe for all motors. Is it because motor is not getting lubrication with oil/gas mix? I never even thought twice about that one. Also, I changed all the fuel line stuff. ie hoses, new fuel pump, new tank and bulb, cleaned carb. The motor sounds great when its running. I will buy a better manuel. I have a generic one but I think I need something that is more specific to my motor. I will then check timming/link/sync per your advise. Regards, Dave J

Re: 1968 Mercury Outboard 35HP Twin

A search on the net for "boatinginfo.no/libary" might get you more info for your motor. Ether starting fluid dries the rod and crank bearings and dose not help seal the rings as the oil at startup dose. Damage to these parts can be done as the do need the oil to lube them. JMO
Oldman570

Re: 1968 Mercury Outboard 35HP Twin

Dave;

What is the s/n of your engine?

Gerry

Re: 1968 Mercury Outboard 35HP Twin

s/n 2341342

Re: 1968 Mercury Outboard 35HP Twin

Your engine is a model:

1350108 MERCURY 1968 35

Parts List:

Mercury Parts, MERC 350

Service Manual P/N: 90-68647 Covers many engine models

Here is a link to the condensed version of the Clymer manual. Download it soonest to your computer as the link is short lived.

Small Engine Repair Reference Center Home

Gerry

Re: 1968 Mercury Outboard 35HP Twin

Thank You Gerry, This information is quite helpful. I have knocked my brains out looking for some information with little success. This should help me discover the problem with my slow-start motor. Thank You to both of you for your time and good information. Happy New Year!!. Dave J

Re: 1968 Mercury Outboard 35HP Twin

Are you rope or electric starting this engine?? I assume you are priming the carb with the hand bulb? Is the choke working, assume its also electric? Good compression?

Re: 1968 Mercury Outboard 35HP Twin

Most of those old Mercs like LOTS of choke on cold start. Make sure your choke linkage is operating and is closing the choke fully... Slop in the linkage may result in only partial choke, which leads to hard cold starting.

Re: 1968 Mercury Outboard 35HP Twin

Don't use starter fluid ... gas/oil mix much safer for the motor. Is motor electric start ? Sounds like you're not getting fuel to start. Are you choking it ? Could also be inside carb - cleaning / rebuild needed. I'd go over the fuel tank, hoses, check that the primer bulb is correctly installed [arrow toward engine] , fuel filter clean ??

Re: 1968 Mercury Outboard 35HP Twin

Thank You Quicktach, The motor is good now. At the beginning of my troubled motor, I changed most everything in the fuel feed. I was about to give up but I checked the fuel filter again. It was clogged like crazy. The things I did not change, like the brass fittings to fuel pump, brass fitting at the entrance of the fuel intake into carb.divice that pugs into the motor from the gas tank. I guess there still was crud in those areas. I'm guessing that when I first tried to start the motor, the fuel pump sucked all the little pieces of crud through and into the fuel filter on top of the carberator. I just could not believe it when I opened it up. I was expecting a big waste of time. When opened, it was almost completely clogged . Once cleaned, the motor started instantly. It has been starting within just a couple of turns of the flywheel now. That was the problem. I guess the moral of the story, check your work. Thanks Again, Dave J