2003 Johnson 150 fuel issue?

[wmich]

Hello all,


I have a 2003 150GLSTA and I'm pretty sure I have a fuel issue and would like some advice.


Was having some problems in the spring, engine at wot won't go above around 4000 RPM with a load. Took it into the local shop, they said good spark and compression. Ended up replacing a thermostat that was stuck. They ran it in the water and I got it back and all was good for about 3 weeks. Same problem came up I took it back in and they said the other thermo was bad as there was some small pebbles in it told me not to run shallow,which I try not to. Water tested, all was good for another few weeks. Now its happening again, this time I checked the thermostats and they are fine. I don't get any audible alarms or lights.


If I push the key in for a few seconds at WOT it will pick back up and run fine until the next time I fire it up and try to run. No problems starting or idling, gets on plane fine.


What are some things I can check before I take it to another shop? I replaced the fuel line and bulb(OMC) when I got the boat about 6 years ago.


Thanks in advance,
Eric

[Bassmeister]

You have a fuel restriction, check the anti syphon valves on the tank, either knock the ball out or go with new elbows...

[Troy250]

You have a fuel restriction, check the anti syphon valves on the tank, either knock the ball out or go with new elbows...

X2. Try this 1st. I chased demons for months and found this to be my issue. Part is only $15 or less, so your not wasting a bunch if this isn't the issue but a cheap place to start!!

[wmich]

I pulled the valve and knocked the ball out. I won't be able to water test until later this week. Fuel lines seem free of obstruction.

Thanks again and I'll report back later on.

[frankfish]

This post has me curious. Can you guys tell me what diameter the anti siphon valve ball is and possibly send a pic? I ask because back when I was trouble shooting my fuel restriction issue I found a small ball bearing lodged in my VRO oil line between the sight tube and pump inlet. To this day I have no idea how it got there? Sorry if I raided your post but maybe in the long run this might help you.

[ChampioNman]

I'd check the high speed orifices and make sure they are fully seated in the carb bowls. To do this, remove the air box and then remove the brass slotted plug from the bottom of each carb bowl and let them drain. Then insert a small #2 straight blade screwdriver into each bowl and "feel" for the orifice. You'll feel is to into the slot for the orifice turn them clock wise gently until you can't turn them any more. Then replace the drain plugs and flush the belly pans with fresh water.

[Randyy]

http://www.bbcboards.net/showthread....t=#post6369972

[wmich]

Update: knocked the ball out of the anti siphon.

First run down the lake all seemed good. Next time down the same problem came up. Push the key for a second and she took right off.

I checked the orifices on the top carbs on each side. They were seated good. It's going to be tough to check the other four especially the bottom two. Is there trick for working in that tight of a space?

[Bassmeister]

dropping the lower pans helps....4 bolts.....

[wmich]

Super old update, found a much better tech to work on the engine. Turned out to be warped carb bowls, got them replaced last spring and all is well again. We now have non-ethanol gas nearby, thank God

[fastman151]

Just out of curiosity....over the years it seems that a lot of issues with Johnson - Evinrude motors has been attributed to warped carb bowls. Is this a problem faced by any of the other major motor manufacturers?

[louievito]

i just had my carb bowls and all lines replaced last fall for the same reason. she didn't want to idle to well but once on plane it was okay. took it to my mechanic and he called the next day and send sent me pics. the ethanol just destroyed everything. warped bowls, all seals and gaskets were mush. 1k worth of work because what I thought I was doing was right. every time I put gas in (usually e10) I used marine stabil. it appears this stuff just slows down process not eliminates the separation. I use only ethanol free now and glad I caught the mistake before it became worse

[Bassmeister]

Warped bowls most times is caused by over tourqing.