90 SN 351 idle problem

it is short, so is my patience...

don't know what the timing is I don't have the boat in front of me.

conv was done to spec. there is no timing problem currently; it has been checked over by a third party as well.

the choke is sticking on start up so I have to open it manually to start. I may be getting gas either on the dipstick or out the exhaust, regardless I'm burning more fuel than usual.

btw that link is great tommer!

Check out this link.

http://www.recarbco.com/technical/newtrouble.html

I find it pretty helpful

in other words you realy don't have a clue on the order of things and how the engine should be set and that your idle starts with the timing and idle mixture screws and idle screw in that order.

you have to set the timing and dwell, if points, then you adjust the idle mixture screws and then you adjust base idle, then you adjust the accel pump and choke if needed.

Your just shooting in the dark guessing at crap, otherwise you wouldn't be dicking around with items that would effect the whole rpm range and not just base idle.

so what is it set at? just because you set it last year doesn't mean it's correct now.

have you set the timing correctly? if it's off then you've been waisting your timing messing with the carb and have to start over.

Kylecraft:

My thoughts:

1. Your carb is flooding the engine, hence the poor idle. May be choke AND/OR needle valve related.
2. The excess fuel in the cylinders (when engine not running) is seeping past the rings and contaminating the oil with fuel. A new carb or rebuild of the one you have will fix problem. Do it soon, or the excess fuel in the cyliners will contribute to excessive cylinder wall wear and loss of compression (the fuel washes the oil off the cylinder walls).
3. The linkage issue is common. Fine adjust the linkage at the transmission end. The neutral safety switch is preventing the starter from operating due to the misadjustment.
4. Low oil pressure at idle could simple be a faulty sending unit or poor electical connections. How low is low? 20psi on a warm engine I have seen before.

Good luck.

haha funny Since I got this boat I thought the worst from the get go; blown case, block, trans, etc.. The engine runs hard, so I hardly think its blown (I've never "blown" a 4 stroke motor b4; only 2stroke), but you never know I guess.
this boat has been a nightmare; at least 7k so far into it and I bought it for 14k CAD 4 years ago. It is a nice boat, just neglected badly and I am the bearer of the abuse. The hull is still very strong as well so once I get the motor worked out and some renew graphics it will run mint just gotta get to the bottom of it

thanks for the quick replies everyone.

as far as the gas in the oil; would this rear its head even if compression tested normal?

could some kind of hydro-lock cause this problem? a bad seal or clocked vent maybe?

I have a sneaking suspicion its carb related, but obviously I'm being optimistic.

I don't know for sure if there's gas on the dipstick. I changed the oil on saturday and ran the boat for 3-4 engine hours all weekend. It ran great save for the poor idle and choke sticking.

The oil is dark in color now and dirty, and smelled like gas I thought, but not sure. Its quaker state synthetic 10w30 which I haven't used before (only used reg. 10w30). I checked the dipstick a number of times on sat and sun to make sure I had enough oil in the case and couldn't even see it on the stick; it was so clear. Then after an hour or 2 on the water yesterday and today (monday) the oil is dirty???

any other hints? I am having my mech. look at it this week and although he is better than I at these kind of things (I did have a 79 supreme with a 351 for 7 years) he is in business and I am not...

all help is graciously appreciated.
cheers,
KC

Another thought for the CCFan research dept., would a cracked or broken ring result in a mixing of fuel and oil? Would his compression test indicate a cracked or broken ring?

I am having consistent problems with this boat and don't know what to do.

I've replaced the tranny, starter, battery, coil, new conv. to elec. ignition, comp. test last year that was great.

so up til now I thought all I needed was a carb rebuild; not so sure now, but I will order one from dim this week.

at idle the boat will stall when it gets warm; there's little to no oil pressure at idle whether in gear or not. Other than this the boat runs great at speed. so I turned up the idle speed to compensate. Now with the idle speed set high I seem to be getting gas on the dipstick and I am burning more fuel and you can smell it and see it in the water (don't know if its related)

Other problem that is connected is the choke seems to stick so when you go to start it sometimes you have to pull the arrestor off and open the choke manually - starts right up and no problems running it after that. It will also start right up usually if you turn it off for just a few minutes, more than that and you have to open the choke manually again...

other problem is the linkage seems to stick so when you go to start it from time to time it wont turn over at all - the guages work and all you have to do is fiddle with the throttle back and forth and its fine - I know its the linkage, how do I fix it and would it contribute to my choke and fuel problems?

so just a recap, I know its a long one and any help is much appreciated.
1. poor idle
2. fuel in crankcase
3. throttle linkage - wont start