73 115 inline 6

MN Fisherman

Recruit
Joined
Jun 11, 2007
Messages
3
I have a 1973 115hp inline 6 that is giving me gray hair. My father in law gave me this boat, and it is in great condition, but it wont always fire. I have had it running about 5 times now, and when it fires it runs absolutly perfect. Then when I try starting it again it has no spark. Any suggestions would be great.

MN Fisherman
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 73 115 inline 6

i had a 71 1350, that i put a new internal wiring harness on, made a huge difference. check for frayed wires, remove and clean all connection, screw and bullet type. Maxrules.com technical assistance, and here's other info:
http://www.boatpartstore.com/page26.asp
 

jackc10

Cadet
Joined
Jun 12, 2007
Messages
10
Re: 73 115 inline 6

All the above is probably true to check and test.

Those old inline 6's are often just hard to start. I do not know why but mine (about a 1984 115) starts easily when connected to a garden hose at home or in the shop but is a mule to start in the water. Always has been and it seems a trait shared by all/most of them. I have tried all sorts of techniques, gas types etc. Runs like a top all day once it fires and starts easy until it sits up for a week or longer.

If all else fails, spray some Quick Start Fluid in the carbs and it should start right up. I have been using the stuff for about 20 years now 90% of the time when I get tired of spinning the starter, with no ill effects.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 73 115 inline 6

qiuick start is worse thing for a 2 stroke, premixed gas in spray bottle or squeeze bottle. the reason they start easier on muffs, is that there is not back pressure on the exhaust. my 71 1350 i had to pump the bulb till hard, then choke, fast idle lever all the way up. turn over 3 tries, then go back to the bulb, pump hard, then use my weight for 2 more pumps, then retry and would start. you have to nearly flood the inline 6's when cold.
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: 73 115 inline 6

Any carb'd motor is sensitive to being level when it's trying to start. If I take the time to get my 150 level, (usually trimmed partly up) it pops off in a second. If I have it too high or tucked, either one, it balks. Once it's been running, I level it, and bump the key for 1/2 second and it's running at idle.

That could be the difference between the flush set and the lake.

hope it helps
John
 

MN Fisherman

Recruit
Joined
Jun 11, 2007
Messages
3
Re: 73 115 inline 6

I have been told that it could be the switchbox, but if the switch box was bad would I get lucky and have it start sometimes?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,102
Re: 73 115 inline 6

MN, You need to find out if you have spark at the no-start times. Put an inductive timing light on the coil to distributor wire and crank the motor. If no spark, you need to go through Clam's troubleshooting procedure. I do not have it handy, but it should isolate the problem to the switchbox or trigger. You need to make sure the motor's wiring is good, before replacing or testing anything. Check the FAQ to find the troubleshooting proceedure.

BTW - I had intermittent spark on my inline six. It was the trigger. Just one data point.
 

OldMercsRule

Captain
Joined
Nov 30, 2006
Messages
3,340
Re: 73 115 inline 6

If yer wiring harness is in good shape I also suspect a trigger, (but ya must eliminate the switchbox first). I must be the only one on here that has good starting inlines, or maybe I have the proceedure down pat. I have not had starting problems with all my old girls. I keep 'em level have a hot battery n' caboom thars fire in the hole!! Good luck JR
 
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