Yamaha 30AE 1983 2 stroke - Bogging Down

[Kev_03]

Hi all,

I hope some of you will be able to help with this stubborn problem I'm having with this YAmaha 30AE 1983 engine. It's an old engine, but it's in excellent condition for it's age having done most of it's work in fresh water.

The problem I'm having is boggin down. It doesn't seem to happen straight away. Yesterday after some work on the engine I decided to test it. I done a 15 minute run at 3/4 to full throttle without any problems. When I stopped running the engine it sat at idle great. When I went to take off again it bogged down.... I was getting a spurt of revs every now and managed to get full revs only once more & but couldn't get full revs at all.. The problem seemed to get worse as I limped my way back in.

I've done some work on the engine and though I had this problem solved...

So far I have fitted new plugs and impeller.
I have fitted a new carb kit, although to be honest the carb looks very clean. I recently cleaned the fuel pump with some carb cleaner and did notice some gunk while doing this. I though I had the problem solved until that run yesterday.

Any thoughts any of you guys have to help this stubborn problem would be greatly appreciated.

Thanks,

Kevin

[Kev_03]

A little bump...

Any thoughs anyone??

[99yam40]

If you found some gunk in the fuel pump then maybe some found its way into the carb and is plugging up the main jets from time to time.

All you can do is check to make sure the timing is advancing properly while the problem is happening, and check to make sure you are not loosing spark too. An inductive timing light hooked to spark plug wires should tell you that.

If you have good compression, spark, and timing then you are left with fuel problem.

[Kev_03]

Thanks very much for for the suggestions...

I cleaned the carb with carb cleaner and TBH, it didn't need doing. The carb looked very clean, but I done it anyway and didn't find any gunk anywhere else.
Do you have the timing settings for this engine.?? I don't have the tools to test it, but will see if I can get a loan off my mechanic brother.

I think the compression is good because I'm getting some good running and then it acts up. I got 20 mins at WOT the other day and the engine sounded sweet... didn't even blip...

I'm thinking fuel as well... Is there any adjustment on the carb that I can make that might help??

Thanks again,

Kevin

[Kev_03]

I checked the compression today.. Was getting 140ish on each cylinder so no problems there. Does anyone know the correct timing setting for this engine?

Thanks,

Kevin

[Kev_03]

While trying to test the timing I was not aboe to get the strobe to function on lead 1. The light was firing on lead 2. I checked the spark and seemed to have a spark on both plugs.
I started the engine and removed the lead from plug one and to my surprise, nothing happened. When I run the engine and remove the lead from plug 2 the engine dies.
I am thinking that the spark that I'm seeing one cylinder 1 is very weak and I'm getting partial ignition or none, hence the bogging down.
When I looked at the flywheel inspection ports, to my horror I saw that there are points and a condensor on this engine. It would seem that this 1983 engine was the last before Yamaha moved to electronic?? Anyway, none of the documentation I can find anywhere gives any details as to the testing of the coils and points gap. Can anyone help with this one?? Does anyone know where I might get a set on points and some condensors?? The flywheel has never been off on this engine, so I will need to replace these parts.

Also, I am giving some thoughts to converting this spark to electronic and would welcome any thoughts anyone has on this.

If anyone can chime in on this one, it would be greatly appreciated.

Thanks,

Kevin

[99yam40]

I do not think many if any have seen that old of a Yamaha motor, so you may have a long wait for some reply.
Good luck with finding a service manual for it.

[Kev_03]

I do not think many if any have seen that old of a Yamaha motor, so you may have a long wait for some reply.
Good luck with finding a service manual for it.

I was thinking that... Thanks very much for your help with this one.

I think the last resort with this one might be an Oregan type electronic module to replace the points and condensor. I have no idea where I might find the points and condensor.....

If anyone else has any info that might help, please feel free to jump in

[99yam40]

Something to check on would be a spark tester, a meter, and DVA adapter for measuring voltage to coil. And ohms on primary and secondary of coil. Even without manual you can compare the two coils

I know on my 99 C40 the inductive timing light had to be turned around when hooked to plug wire ( arrow pointing away from plug)otherwise it did not operate the timing light

[Kev_03]

Hi all,

Just an update on this one. Would anyone have the coil parts numbers for this motor. Thanks to a mistake I damaged the coil when removing the flywheel. I need to pick a new one up.

Thanks,

Kevin

[Kev_03]

The plot thickens2012-04-20 20.02.54.jpg2012-04-20 20.03.08.jpg2012-04-22 13.40.25.jpg2012-04-22 13.41.24.jpg....

I have been digging everywhere for the coil part numbers for this motor and have come up against a wall. I have 2 ignition coils, I have been told that parts listings for the Yamaha 25D and 30A suggest a single ignition coil. I have included a few pictures of the coils that I have. If anyone can help ID the part numbers it would be great. Also if anyone know if I can replace this dual coil setup with a single larger coil as suggested to me.

Thanks guys,

Kevin