Outboard wont cold start in the ocean.

[boostin_7]

My outboard starts no worries with a flush attachment, but when i try to start her in the water at the ramp all she does is soak the plugs.
Last time i tilted it up out of the water, it fired up & ran straight away then i quickly dropped it back down into the water.
After its started once & warm it will restart without a problem for the rest of the days activities.
Any ideas on whats wrong?
Could it have anything to do with back pressure on the underwater exhaust outlet when its in the water?

By the way its an old 1966 100hp V4 outboard

Regards
Greg

 

[JB]

Re: Outboard wont cold start in the ocean.

Back pressure in the exhaust system is causing your trouble. You need to do a link 'n' synch with the foot in water.

Good luck.

 

[kfa4303]

Re: Outboard wont cold start in the ocean.

yup. on the muffs, there is little if any back pressure for the motor to contend with, so it can very easily be started, especially if it's a large motor. however, on the water you have much more back pressure pushing back against the exhaust gasses produced by the engine. it's like trying to blow through a straw with your finger covering part of the opening at the other end. you can still do it, but it takes more effort. Try adjusting, dialing in your carb's at idle while on the water. If it's flooding a lot, you'll probably want/need to lean the mix out a bit. Here's a link to help you set up the carb(s).


http://forums.iboats.com/showthread.php?t=167352

 

[mekkamaz]

Re: Outboard wont cold start in the ocean.

It has hydrophobia!! LOL...

Try the upstairs solutions and post any results...try to help from there...

 

[boostin_7]

Re: Outboard wont cold start in the ocean.

thanks for the advice guys, ill try your suggestions this weekend

 

[boostin_7]

Re: Outboard wont cold start in the ocean.

Looking at my carb adjustment, all the needle valve are attached together with a plastic rod style setup.
Would i be able to solve my issue with just doing slight 'batch' adjustments to all needle valves by moving the rod toward the lean position?

 

[boobie]

Re: Outboard wont cold start in the ocean.

You can remove that linkage and adjust each needle individually for starters. Screw the needle in until it seats and back out 1/2 turn. Put it in the water, have in fwd gear and then fine tune them. Then put the linkage back on.

 

[boostin_7]

Re: Outboard wont cold start in the ocean.

I finally got the chance to have play with tuning the carby this weekend. Im not 100% certain ive got a 'good' tune after my adjustments but its easier to start with the leg in the water.
No matter what i do though, i need to heavily choke the engine on cold starts for it to fire up.

Also the engine runs rough on a light amount of throttle when im taking off & then when it smooths out with more throttle & then seems to constantly creep & accelerate by itself.
I was hoping tuning the carby would fix this but i have had to success so far.
I was chatting to an old outboard mechanic later on & he said that there should be a mixture adjustment separate to the carby needle valves, which needs to be adjusted to fix this problem.
But i cant seem to find what he's talking about in the service manual for me outboard.