v-150 idles worse as it is tilted down

[airwalkin]

Hey all, I'm running a V-150, serial 5301115 (1979 vintage). I find it seems to idle worse when trimmed all the way down, sometimes stalling. When I trim it up some, idles fine. I noticed this in gear, as I was trolling through a channel between lakes. Could it be an engine problem, or the lower the prop, the more pressure to turn it? Thanks.

 

[AndyL]

Re: v-150 idles worse as it is tilted down

I would imagine that this is purely a function of exhaust back pressure. The more you trim down the greater the hydrostatic head of water pressure on the exhaust. This would affect the fuel mixture. I always had to trim out my 135 on low idle in the same manner you speak of.<br />Andy

 

[shipoffools]

Re: v-150 idles worse as it is tilted down

It is also possible that float adjustment is to blame the angle of the engine will cause a chnge in fuel level in the carbs causung it to starve or flood

 

[hondon]

Re: v-150 idles worse as it is tilted down

Check or replace all of your recirc bleed lines and check valves.This is a classic example of recirc failure.

 

[airwalkin]

Re: v-150 idles worse as it is tilted down

Alright, thanks for the suggestions. I'm not sure what you are talking about though hondon, with this recirculation system. Can you explain? Thanks.

 

[hondon]

Re: v-150 idles worse as it is tilted down

I,ll try.Your two stroke engine draws fuel into the combustion cambers because it has compression on both the down and up sequence of it,s stroke.On it,s up stroke it is drawing fuel and air mix from the carbs past the reeds and into the crankcase where it lubes the crank bearings and is drawn into the cumbustion chamber to be consumed.Problem is that space between the reeds and chamber is nice and cool and that fuel mix your carb has so nicely atomized likes to puddle up in there.So here is the recirc system that takes those puddles and sends them where they are more usefull.Recirc problems are almost always more evident at idle and generally improve when tilted up.

 

[Laddies]

Re: v-150 idles worse as it is tilted down

as you tilt a v/6 under it runs rich and as you tilt it out it runs leaner so your float levess are high

 

[JasonJ]

Re: v-150 idles worse as it is tilted down

Does the motor sit low in the water? It is posible that the exhaust relief is submerged when trimmed all the way in if the motor sits low due to design of the boat. A boat with a lot of deadrise will end up with the motor sitting low when at rest. The floats being out of wack or needles not seating is another possibily, as excess fuel will flow into the engine when trimmed in, whereas it'll flow out of the carb throats when trimmed out. Good luck...