Tohatsu M15B2 (1986) issues. Is it my coil?

[rookieboaterj]

I've been having issues lately. at first, i had issues with going high speed. Just after planing, the boat would quit, like starved for gas. I replaced tank, lines, primer ball, diagprams in fuel pump, and cleaned the heck out of the carb. still had the same issue. so, i cleaned the carb AGAIN, and still the same. I started fiddling with wires around the igniton coil, and stuff started changing. I'm now able to go wot no problem.

The issue: I cant go trolling speed. Anywhere below 3mph and my motor starts sputtering and dying. Is the ignition coil causing my troubles? Carb is super ooper dooper clean.

By the way, as i was testing my troll speed yesterday, i of course had a line out, and caught a king salmon.

 

[pvanv]

Since parts are NLA, proceed carefully. If fiddling with wires makes a difference, you know there is at least one questionable connection. Start there.

 

[Sea Rider]

All electrical connectors & grounds, must be immaculate clean and shiny for all electrical parts to work spot on, check each, clean, reconnect. 30 years is a lot of time.

Happy Boating

 

[rookieboaterj]

Okay, i've some new information.

Here are my symptoms:

Sometimes able to troll speed, but if i go too low, it chuggs and spits and dies.
Sometimes able to go cruising speed, but if i take it back down to trolling speed, then try to get back up on step, it simply chugs and chugs like it doesnt have enough fuel.
When i turn the throttle up while idling, it will smoke and i can hear the rpms progressively get higher. It doesnt jump up to the rpm it should be, but slowly brings itself up.
If i take the motor cover off, it has an easier time getting up on step.

What i've done:
Replaced ALL components of my fuel pump. Everything is brand new.
Replaced ALL fuel lines, primer ball, and fuel tank.
Using new clean gas, with perfectly ratioed oil/gas. I use a measuring container for the 2 cycle oil mix. (50:1)
Cleaned the carb SEVERAL times. Went through EVERY port/tiny hole/every piece and used industrial strength carb cleaner, and compressed canned air, and a 150 PSI air compressor with a needle hole air blaster attachment, as well as sewing needles though every tiny hole to ensure its cleared. I've also soaked the carb in seafoam, as well as the deep creep treatment overnight. It did not seem to change very much.....
Ignition Coil is only about 6 months old, but the wires on it were crap, and i had to re-splice into those wires as the connections were bad. I've got it connected well, but went ahead and ordered a new ignition coil. It should be here tomorrow.

My questions:
It doesnt appear as though there is a gasket between the carbeurator mount/hole before the red valves. Can i safely take it off to inspect my reed valves? Do my symptoms sound reed-valvish?
Removing the lid, to me, means its getting more air in the intake, so is maybe that connected to the reed valves not letting enough air in, but when the covers off, it has more air coming at it, and is able to fix the ratio?
I've fiddled with the air/fuel mixture needle a lot, doesnt seem to change anything, unless i close it all the way, it kills the motor. I've kept it at the recommended 1.5 turns out.

Any suggestions on the next step to take?

Are my symptoms indicative of compression issues? I dont have access to a compression tester..... but if these symptoms are compression related, then i can order one.....

Please help!

A king bit my herrings tail off today. I'm not rich, and really want to get my motor going so i can just fish. As it it, im restricted to the area by the harbor. I'd love to get this figured out so i can venture further, to the real good fishing holes.

Please advise.

Josh

 

[Sea Rider]

Josh,

If Ignition Coil cables are kaput, dried, cracked should be loosing power, could check sparks coming from cables in a dark place such as a garage with OB on. A new IC and plugs is the way to go.

Personally having such an old nice OB would tear cylinder head, clean all water paths on entire crankcase, clean both crankcase and cylinder head mating surfaces to be even and smooth and install a new head gasket, torque in 3 steps of 10 NM each till 30 NM is reached. Cylinder head gaskets issues are not mentioned on any service manual, but they do give issues which are very complicated and head breaking to diagnose properly. Head gaskets with time compresses, dries, craks, rusts, corrodes inside powerhead.

If going for a new IC/Plugs does not cure the disease assuming all other 2 related electrrical parts are in 100% working order change head gasket, will need to order a base gasket & thermo gasket along. If OB has not been flushed after use specially in salt water for such long years of use, could have excessive corrotion on gasket which lests tiny water dropletes inside combustion chamber and engine works erratically bad. Post your findings..

Happy Boating

 

[rookieboaterj]

Still waiting on my ignition coil. I discovered that my work had a tohatsu service manual and electrical component supplement for my motor. Pretty stoked about it. Reading through it, i came across timing. I was fiddling with the components in the throttle to make it less resistant to turning on my tiller, and may have messed up the timing when i put it back together. Would that cause ignition issues similar to mine?

 

[pvanv]

It sure could.

 

[rookieboaterj]

Shipping sucks to rural alaska. Still no new IC yet. Gonna go use my new found manual to test all my wires and fix my timing and get everything to spec. I'll be testing all wires. If all checks out, then its going into the shop tomorrow for a compression test. Maybe me throwing the timing off has ruined the coil? Hopefully not the CDI, they are expensive.

 

[rookieboaterj]

Well now!!!!

Equipped with my new service manual, i started doing electrical diagnostics. I tested the IC, and primary coil test was success. secondary coil test gave no reading.
When i went to reconnect it, figuring the IC was bad, the IC lead coming from the CDI just popped right out of the CDI.

I realize now that when the cover was coming off/on it was jiggling that wire. I bore my way through the cdi to where the wire came disconnected, and soldered a new wire to that point. put everything back together, and shes idling WAY better. WAY WAY WAY better.

There is still some chugging and backfiring it seems when i try to get super duper low idle.
I need a tachometer!
Anyway..... Could the IC secondary coil have been broken due to the connection between IC and CDI being barely connected?

I think my problems are mostly solved.... maybe

Please advise?

 

[pvanv]

The secondary resistance (plug wire to ground) should be almost infinite, on a Very accurate Analog meter.

 

[tommarvin]

Salmon almost always strike short, you want the EYE of the hook at the very end of the tail, trailing loose for them short strikers.
cdielectronics.com is the king of new ignition parts,and how to testing all ignition parts,look up your parts.

 

[rookieboaterj]

Yeah so i think it was definitely my power pack. my solder job popped off, and took the whole contact on the cdi chip with it, leaving me SOL on fixing that one. Next step is to order a new one. I noticed that my tohatsu m8c doesnt have a power pack, it has the wires coming out of the flywheel going into just two ignition coil deals. Since its two stroke as well, would it work if i took the IC setup out of the 8hp and put it on the 15hp?

 

[pvanv]

M8C? Never seen one in the US. The M8B had a combination CD/siamese ignition coil.

 

[rookieboaterj]

I definitely have an M8C. Its weird, because on the parts diagram list on boats.net, i cant find the m8c, only the m8B, which has a different carbeurator.... idk.

At any rate, if i take the combo CD/IC deal off the 8 and put it on the 15, will it work?

 

[rookieboaterj]

Sorry, its an M8A.

Anywho,

On my 15, I took my block apart and saw that my upper bearing shattered. ball bearing pieces and gouges in the crankcase side of it, but the cylinder was fine. Rings were like... welded to the piston. Replaced the piston with parts motor piston, and have ordered rings and gaskets. I'll update when i finish, as i hate looking through forums only to see the OP never came back to say what ended up happening.