Tweet
Put a fresh factory powerhead on my C90. Everything seems to running fairly decent, got 4hrs on it. Im having a issue that even the old powerhead and previous owner told me it always had and the new powerhead is doing also. In cold weather 55deg and lower, it takes a long time to clear its throat/warm up. I will let it warm up at the dock for 5 minutes idling, and them putt out of the marina into the channel. Go to give it throttle, and it just boggs at 2000rpm and wont go any higher for about 10 minutes. Have to let it warm up more, turn it off to heat soak a little, then clear it out and finally it will get up to rpm and plane out to WOT. I did link/sync the carbs/timing and verified with a timing light today at idle. I did take a look at the electrothermal enrichment valve/solenoid. I pulled it off last night, and it did NOT ohm out properly on the black/blue wires with a standard $20 digital volt meter. I only got about .02-.07ohms. I did put it on a small 12V battery, it got warm, and the needle assembly did move out some over about 5 minutes. I noticed there is no o-ring on this assembly where it bolts into the carb casting which I thought was kinda odd. Even on the boats.net diagram, it shows no o-ring unless its part of the assembly and not shown. Im wondering if the valve is not working correctly and if there is supposed to be a o-ring on it? If anyone has experienced this cold weather issue, any help is much appreciated. Engine is on a flat bottom 16ft flats scooter with a tunnel. No V in the hull. Getting about 36mph at 5,000 with a slight tail wind.
-
-
I've been running a 1999 C90 since I bought it new and it's never taken more than a few minutes on fast idle at the dock to get warmed up and go, so it does sound like you have an issue...maybe your thermostat is not working correctly...easy enough to remove it and give it a check.... -
As I recall there should be an O ring between the primestart device and the body into which it sits.
Also, make sure the the device is in the automatic or on position, not the off position.
Last edited by boscoe99; 12-16-2015, 09:02 PM.Comment
-
The thermostats are changed once a year, and this one is 4hrs old along with the entire powerhead from factory Yamaha. I have the red fuel supply valve to the ON position. Does anyone know the part number for that O-ring? I cannot find it to save my life.Comment
-
The O ring is part of the device.
I would just go to Home Depot, Grainger, Fastenal or some place similar (maybe a hydraulics shop) and see if I could find an O ring that would work.Comment
-
There looks to be a groove on the bottom of the valve body that im assuming the o-ring would sit in and seal against the carb casting?Comment
-
Any idea about it reading weird on the ohm meter?Comment
-
Took it out again this morning in cold weather (50deg) and it took a long time again turning the engine off and on. The pee water was warm. Im really thinking that valve/solenoid is faulty. It was on high idle 1400rpm for a long time. I turned it off, let it sit for about 1 minute, turned it back on and the idle was right where it was supposed to be and engine had full power. Just that simple key off and then re-start changed it.Comment
-
Some Prime Start devices have 3 positions, on, off and normal/automatic....the on position is just that, continuous enrichment, and the off is just that, no enrichment at all....you want normal/automatic which is a fully automatic hot wax pellet actuated plunger enrichment...very similar to a thermostat...seems like to me that a slow warm up of the motor might be related to the cooling water thermostat more than the mixture enrichment. Like I mentioned, my C90 warms up quickly...only real reason I let it warm up at fast idle for a few minute at the dock is it's highly recommended by Yamaha for the life of the motor. Let us know what you find out!....Comment
-
The powerhead itself is warm and the water coming out is warm after a few minutes. It seems like its not getting enough fuel when I go to give it throttle, even backing off the trailer its got a bog. Once it warms up, its got more of a 2-stroke pop to it and the idle lowers down to 950 or so. Along with a new primastart valve, I ordered a new diaphram and gaskets/o-ring for the front side of that assembly.Last edited by flounder daddy; 12-17-2015, 06:12 PM.Comment
-
Well, I hope the Primestart rework helps with this issue....keep us posted!Comment
-
Will post when new stuff is installed.Comment
-
parts installed, took it out wednesday and it ran great. But then again, it was almost 80deg here wednesday. Fishing was good as well! true test will be tuesday when its forcasted to be in the 50s. Santa left me a Garmin 54DV gps under the tree last night. Installed it this afternoon.Comment
-
Keep us posted after you do a cold morning start-up....Comment
-
Same thing with new solenoid. Its almost like its carb icing or something. Had to turn it on and off 4 times and finally it ideled down and off we went. Was 45-50deg air temp yesterday. Did steller fishing, but that cold weather deal is annoying. I dont think the carbs need a cleaning, got 4900-5000 out of it WOT with 3 guys on heading into a 20mph head wind/chop. I read a post on a forum somehwere where a guy had a similar issue and it ended up being the o-rings on the air-box to the carbs. Cheap enough to try anyway.Last edited by flounder daddy; 12-30-2015, 01:20 PM.Comment
Comment