1997 70HP - Tips for cold start

[Yammie70]

Hi,

I have a 70HP (BETO) that is quite hard to start the first time. Once the motor has been started once, then it starts really easily, it's the very first start of the day which can be a real pain in the ass.
It took me about 30min to get it going last time, so I'm chasing some tips or a sequence that works well on this model.

Here is what I usually do:
- Tilt the motor down
- Press the bulb a few times until firm
- Fully open/close the throttle 4-5 times
- Set the throttle lever about 50% or more
- Turn the key until it fires. Sometimes moving the throttle up and down a bit helped to get it going. Once I can hear it fire at least once, then I know it will start on the next try.

Sometimes I have to keep the starter motor running almost a full minute before I can hear it fire, which is not great for the battery but persistence is the only way I found to get it started.

A few additional comments:
- The motor has a prime start system (no choke). I assume it works but I've never disabled or tested it properly. Last time I struggled to get it started I tried moving the red lever out of auto/ normal to open or closed but it didn't make any difference.
- Carburetors have been cleaned very recently
- Spark plugs are clean and almost new
- The temperature is not very low where I live (~60F)
- The compression is even on all cylinders but relatively low (~90psi if I trust my gauge). Could that explain why it is hard to cold start ? Again it starts perfectly afterwards and overall works well.


Any tips or suggestions would be very welcome,

Thank you!

[robert graham]

Sounds like a problem with the Primestart mixture enrichening system…..it’s fully automatic system that acts as a choke for cold starts…

[99yam40]

Pump the primer bulb more to make sure the carb bowls are full.
on my C40 I can hear fuel flowing and then the bulb cannot be pumped anymore, becomes hard and no sound of it pushing thru the check valves in the fuel pump.

next do not play with the throttle at all, leave it in the neutral position along with the fast idle lever, leave it down also.
opening the throttle will deactivate some of the prime start

Do not run the starter more than a few seconds at a time (3 - 5), then let it sit for 5 - 10 seconds between
Should fire up in 2 or 3 try's

you really need to figure out if it is not getting enough fuel or getting too much before knowing how to attack this problem


turning the red lever to open should pump liquid fuel into the manifolds
closed keeps any fuel from flowing.
auto should put an enriched fuel vapor into the manifolds.

[brian3006]

I agree, start with looking at the prime start system. I just had to replace the diaphragms in mine. pretty cheap and pretty easy too.

Also, try it with keeping the throttle at full idle. with it half-open, it is just letting in more air, thus making it even leaner. This would be fine if you had a traditional choke, but you don't.

Also, there is no need to work the throttle several times. There is no accelerator pump to squirt fuel or a choke to reset like in the old cars.


Do yo have the abilitly to check the engine timing? just to verify?

[Yammie70]

Thanks a lot for the advice.

I tried the motor this morning, making sure the bulb was really hard and leaving the fast idle lever down. It started on the second try...It was surprisingly easy.

I think I usually don't press the bulb long enough, as I stop after a few squeezes (5-6). Also I swear fiddling with the fast idle lever while cranking the motor usually helps to get it started but it might have been an illusion...I can't believe I was doing the wrong thing for so long (that said it was a pretty warm day and the motor was sitting in the sun for a while). I have a trip planned in a few days it will be a good opporunity to try again

I'll replace the primestart diaphram, just in case.

[99yam40]

good to hear it stater up easily.
I would not replace anything if it starts up as it should

[panasonic]

Not saying that an engine won't start somewhat easier when its warm weather. But if everything is as it should be it should start in very cold temperatures relatively easy as well. Think two stroke snowmobiles (or four stroke) starting in sub zero temps. I had my boat out last week and it started normally at 2 degrees Celsius ( 34 F) and have started it below zero as well.
Glad you have it sorted out...i am with yam if it isnt broke don't fool with it. Try it a few times more and if all is well...leave it be.

[Yammie70]

Test number 2 today, again it started on the 2nd try...I'll stick to this new sequence as it seems to work better than anything I've tried before.

One thing I do, on top of what was suggested before is to turn the key on the ON position and leave it there 10 sec or so before cranking the motor.
After watching this video https://www.youtube.com/watch?v=x35uqVMu2r0 I thought it could help the get the primerstart system to settle before the motor starts.
I've been wrong before ;-) so hopefully that actually helps and doesn't make things worse...


- Final questions from me: winter is coming where I'm living and I'll use the boat a bit less during that time. I usually try to get the motor running for a few minutes at least once a month.
It's easy enough for me to get it running regularly, even if I'm not using it. What's a good timeframe to do that ? Weekly/fortnightly/monthly ?

[ausnoelm]

I don't think there is any set time to start the motor up, just make sure you have the flushers connected, not too sure if winter for you is freezing temperatures, but take that into considerations when flushing.

[99yam40]

I do not see how turning on the key before starting does anything on Prime start system on motors like mine and yours.

There is a wax pellet in the heater unit that pushes the needle to the closed position as the heater heats up the wax from current sent to it from the lighting coil while the motor runs.( not from the key switch)

When motor is not running the wax cools off , which in turn raises the needle back up( opens the passage) getting ready for another cold start.

I start my motor every once and awhile (2 to 4 weeks)when I think about it if I am not using it often.
mainly to keep the fuel in carb bowls fresh.
as fuel evaporates it leaves residue
My motor is a C40 so I premix, as the fuel evaporates it leaves oil