djarrett
Cadet
- Joined
- Jul 9, 2007
- Messages
- 20
1984 yamaha 150, single bowl carbs stamped 6G401, oil injected. ETLN
Im still having a low wot rpm problem.
Compression= 100,105,102,102,98,100 respectively
The first thing i did was rebuilt carbs. It ran ok for about 1 1/2 hrs then started missing at part throttle again. It still only reached about 5100 rpms. Cleaned out carbs again and found trash in the high speed jets. This time i installed a 10 micron water filter seperator in between the tank and bulb. Ran perfect but still wasn't getting wound all the way up. Replaced fuel line from tank to motor and new bulb. Did away with the engine mounted fuel filter and did away with the quick disconnect at motor. Tank is mounted in boat and pulled the fuel level sender to inspect, did not see any seperation or trash in tank. Pulled the fuel pickup and found no restrictions. Still idled great and runs perfect up to 4700ish r's, but thats all it will spin. Then bought two new fuel pumps and cleaned the carbs again, did a link and sync and set the timing, it still didn't help wot. Have fished all summer like this but i would still like to get it to wind up more.
Now that fishing has slowed down for hot weather i would like to get this corrected. I installed new plugs in the spring and have run around 90 gallons of gas thru it so far this year, ring free and sta-bil always added when gas goes in.
I pulled the plugs friday and 1,3,4,5,6 look perfect. They are clean with a light tan color on the ceramic, slightly damp. Plug #2 is black and covered in either carbon or oil deposits. I dont believe its firing correctly on hole #2 because of the plugs appearence.
Is there anything else i could have missed in the fuel system? Go thru top carb again?
Should i start checking the ignition system now? I do have an older seloc manual but it does not give any voltage readings for the ignition system, only ohms which sucks for real troubleshooting. Coil #2 ohmed out ok, (primary to ground 0.75 ohm, secondary to ground reads 3.5k ohms) this was with a cold motor. Can someone please tell me what voltages to look for at coil primary input. I don't have a DVA yet but i am going to order one.
What is good way to check to see if the coil is dropping out when the motor is warmed all the way up? I have definitely noticed when i first start it up(fires up very easily, about 1-2sec no matter how long its been setting) it idles around 800, but after i run to a fishing spot(1-8 miles) it wants to idle about 500, it has a hot foot so i can keep it idled up manually. As long as i don't run anywhere it will keep the 800 rpm idle. It takes about 20 min. to get out of the no wake zone and it keeps the 800 rpm idle until i run it. After it cools all the way down it will pick the idle back up to 800.
Should i start at the coils and troubleshoot back towards the stator or start at stator and lighting coils and work towards/thru cdi to the coil?
Does anyone know of a good yamaha tech around Cookeville tn? I would definitley be willing to drive a distance for a great tech. I am debating on taking to a marine mechanic, but i am not wanting to pay for splattergun trouble shooting, thats what i'm doing now. I have several fishing partners and seems to me thats what they all pay for when they take their outboards in around here.
This motor is mounted on a 16.5 ft. bass boat and has yamaha 23M prop on it, it should be able to spin this prop like toy.
Sorry so long but i wanted to give all useful info out there first.
Im still having a low wot rpm problem.
Compression= 100,105,102,102,98,100 respectively
The first thing i did was rebuilt carbs. It ran ok for about 1 1/2 hrs then started missing at part throttle again. It still only reached about 5100 rpms. Cleaned out carbs again and found trash in the high speed jets. This time i installed a 10 micron water filter seperator in between the tank and bulb. Ran perfect but still wasn't getting wound all the way up. Replaced fuel line from tank to motor and new bulb. Did away with the engine mounted fuel filter and did away with the quick disconnect at motor. Tank is mounted in boat and pulled the fuel level sender to inspect, did not see any seperation or trash in tank. Pulled the fuel pickup and found no restrictions. Still idled great and runs perfect up to 4700ish r's, but thats all it will spin. Then bought two new fuel pumps and cleaned the carbs again, did a link and sync and set the timing, it still didn't help wot. Have fished all summer like this but i would still like to get it to wind up more.
Now that fishing has slowed down for hot weather i would like to get this corrected. I installed new plugs in the spring and have run around 90 gallons of gas thru it so far this year, ring free and sta-bil always added when gas goes in.
I pulled the plugs friday and 1,3,4,5,6 look perfect. They are clean with a light tan color on the ceramic, slightly damp. Plug #2 is black and covered in either carbon or oil deposits. I dont believe its firing correctly on hole #2 because of the plugs appearence.
Is there anything else i could have missed in the fuel system? Go thru top carb again?
Should i start checking the ignition system now? I do have an older seloc manual but it does not give any voltage readings for the ignition system, only ohms which sucks for real troubleshooting. Coil #2 ohmed out ok, (primary to ground 0.75 ohm, secondary to ground reads 3.5k ohms) this was with a cold motor. Can someone please tell me what voltages to look for at coil primary input. I don't have a DVA yet but i am going to order one.
What is good way to check to see if the coil is dropping out when the motor is warmed all the way up? I have definitely noticed when i first start it up(fires up very easily, about 1-2sec no matter how long its been setting) it idles around 800, but after i run to a fishing spot(1-8 miles) it wants to idle about 500, it has a hot foot so i can keep it idled up manually. As long as i don't run anywhere it will keep the 800 rpm idle. It takes about 20 min. to get out of the no wake zone and it keeps the 800 rpm idle until i run it. After it cools all the way down it will pick the idle back up to 800.
Should i start at the coils and troubleshoot back towards the stator or start at stator and lighting coils and work towards/thru cdi to the coil?
Does anyone know of a good yamaha tech around Cookeville tn? I would definitley be willing to drive a distance for a great tech. I am debating on taking to a marine mechanic, but i am not wanting to pay for splattergun trouble shooting, thats what i'm doing now. I have several fishing partners and seems to me thats what they all pay for when they take their outboards in around here.
This motor is mounted on a 16.5 ft. bass boat and has yamaha 23M prop on it, it should be able to spin this prop like toy.
Sorry so long but i wanted to give all useful info out there first.