I have a 87 o'day w/ a 2gmf20 under full throtle and a load my raw water comes out kind of dirty looking and leaves a trail in the water. ( no smoke) Sort of looks like engine oil? Under half throttle or low speed it goes away. Boat starts easily and seems to run fine. I don't know but this can't be good.
- Status
Probably unburned fuel and/or are 'lugging' the engine
a diesel at WOT will blow soot in most cases when the props pitch is too great and the engine is 'lugging'.
What you are probably seeing is soot in the water.
Changing prop pitch so that you can run WOT at a higher rpm will usually correct the 'sooting'. Look at your engine rpm vs. output torque curves in your manual and see if the engine is actually attaining full rpm @ max. load. Lugging will put tremendous pressure on the pistons, piston wrist pins, etc. Most boats are usually 'overpitched' by the boat builders. Check your engine manual to see if you are reaching max. rpm at WOT.
Alternative and adjacent cause is faulty/worn injector(s) with bad spray patterns - easy to check: remove them and send to an 'injector shop' - every large town has one; injector rebuilds are cheap.
Usually the soot problem @ WOT is too much prop pitch. Check the pitch versus max. rpm - before you pull the injectors.
a diesel at WOT will blow soot in most cases when the props pitch is too great and the engine is 'lugging'.
What you are probably seeing is soot in the water.
Changing prop pitch so that you can run WOT at a higher rpm will usually correct the 'sooting'. Look at your engine rpm vs. output torque curves in your manual and see if the engine is actually attaining full rpm @ max. load. Lugging will put tremendous pressure on the pistons, piston wrist pins, etc. Most boats are usually 'overpitched' by the boat builders. Check your engine manual to see if you are reaching max. rpm at WOT.
Alternative and adjacent cause is faulty/worn injector(s) with bad spray patterns - easy to check: remove them and send to an 'injector shop' - every large town has one; injector rebuilds are cheap.
Usually the soot problem @ WOT is too much prop pitch. Check the pitch versus max. rpm - before you pull the injectors.
Examine, if you will, the components
of the exhaust system: hot air (gas) and raw water (via the hx). The hot gas comes into the exhaust when the valves open. What's inside the cylinders? Hot air and oil, and maybe a tiny amount of unburned diesel fuel. So, there's gonna be some cr*p in the exhaust and it ain't gonna be lily white clean. Unless you're experiencing other issues, you may not have a problem at all.
of the exhaust system: hot air (gas) and raw water (via the hx). The hot gas comes into the exhaust when the valves open. What's inside the cylinders? Hot air and oil, and maybe a tiny amount of unburned diesel fuel. So, there's gonna be some cr*p in the exhaust and it ain't gonna be lily white clean. Unless you're experiencing other issues, you may not have a problem at all.
What is WOT?
Interesting response, Rich... can you please translate to someone who now realizes he knows even less about diesel engines than he thought he did? What's WOT?
Interesting response, Rich... can you please translate to someone who now realizes he knows even less about diesel engines than he thought he did? What's WOT?
Take a dive!
check your prop first for barnacles. if their present then when you try to throttle up your overloading the motor. if its clean then move onto checking the injectors. but before pulling injectors, try putting a quart of ATF (automatic transmission fluid) in the tank with about 5 gal fuel. if the injectors are just dirty this will clean them right up. i put a qt in my tank every spring and haven't had to pull an injector for the 18 yrs I've owned my boat. also works well in your mercedes diesel. Old truckers trick.
if prop is clean, atf doesn't work then its time to pull injectors and have them checked and possibly serviced. let your fingers do the walking for an injector shop. price to check is nominal, usually about 5 to 10 bucks. servicing and or repair is usually less than 100 bucks/inj.
check your prop first for barnacles. if their present then when you try to throttle up your overloading the motor. if its clean then move onto checking the injectors. but before pulling injectors, try putting a quart of ATF (automatic transmission fluid) in the tank with about 5 gal fuel. if the injectors are just dirty this will clean them right up. i put a qt in my tank every spring and haven't had to pull an injector for the 18 yrs I've owned my boat. also works well in your mercedes diesel. Old truckers trick.
if prop is clean, atf doesn't work then its time to pull injectors and have them checked and possibly serviced. let your fingers do the walking for an injector shop. price to check is nominal, usually about 5 to 10 bucks. servicing and or repair is usually less than 100 bucks/inj.
Opposite effects
CapnJim, I thought about your barnacles on prop and overloading the engine.
I dont think barnacles makes the engine work harder, but it does make the boat go slower.
If the boat goes slower, there is not as much power delivered from the prop.
If there is not as much power from the prop, the engine is not delivering as much power. The prop does spin and it has alot of turbulance but somehow I think that the turbulance does not consume as much power from the engine as forward motion does.
Its like the barnacles are re-pitching your prop. So I think that barnacles reduce the load on the engine.
I may be wrong and I hope that someone also comments.
Frank - check your oil level often. This will eliminate or confirm your suspicions.
CapnJim, I thought about your barnacles on prop and overloading the engine.
I dont think barnacles makes the engine work harder, but it does make the boat go slower.
If the boat goes slower, there is not as much power delivered from the prop.
If there is not as much power from the prop, the engine is not delivering as much power. The prop does spin and it has alot of turbulance but somehow I think that the turbulance does not consume as much power from the engine as forward motion does.
Its like the barnacles are re-pitching your prop. So I think that barnacles reduce the load on the engine.
I may be wrong and I hope that someone also comments.
Frank - check your oil level often. This will eliminate or confirm your suspicions.
I disagree
GuyT, I disagree. I just had a short haul done to clean the barnacles off the prop, hull, keel, etc. Prior to doing so I had to push the engine to run at my normal speed 7kts at 2800 rpm. The engine red lines at 3500 and I couldn't get it above 3000. After the short haul I'm running at 7+kts at 2800 rpms and can easily run above 3000 if need be. I'm not pushing the throttle up as far as I did with the dirty bottom. Not doubt in my mind that I was working the engine harder with the dirty running gear and bottom. In addition to the greater power available from the engine, it's now quieter and smoother. The bottom line is that a clean bottom/prop definately makes a difference in how hard the engine works.
Mike
GuyT, I disagree. I just had a short haul done to clean the barnacles off the prop, hull, keel, etc. Prior to doing so I had to push the engine to run at my normal speed 7kts at 2800 rpm. The engine red lines at 3500 and I couldn't get it above 3000. After the short haul I'm running at 7+kts at 2800 rpms and can easily run above 3000 if need be. I'm not pushing the throttle up as far as I did with the dirty bottom. Not doubt in my mind that I was working the engine harder with the dirty running gear and bottom. In addition to the greater power available from the engine, it's now quieter and smoother. The bottom line is that a clean bottom/prop definately makes a difference in how hard the engine works.
Mike
Frank ---
also check for a hot/warm running stuffing box. The friction will 'bleed off available HP' (as a 'prony brake') and be additive to any 'lugging' that may be happening. (Best is to use GFO PTFE braided GoreTex packing/stuffing .... stays dimensionally stable while providing extremely low frictional characteristics)
Barnacle removal will allow the prop to spin faster, removes 'mass' from the fouled prop while increases efficiency.
also check for a hot/warm running stuffing box. The friction will 'bleed off available HP' (as a 'prony brake') and be additive to any 'lugging' that may be happening. (Best is to use GFO PTFE braided GoreTex packing/stuffing .... stays dimensionally stable while providing extremely low frictional characteristics)
Barnacle removal will allow the prop to spin faster, removes 'mass' from the fouled prop while increases efficiency.
Thanks
Thanks Guys, a lot of Interesting suggestions. Soot would be the best to describe it. I'm leaning towards wrong pitched prop. The previous owner replaced the factory prop w/ a 3 blade and its probably the wrong pitch because the max RPM is only about 3000. The bottom and prop were scraped about 3 mo's. ago.
Thanks Guys, a lot of Interesting suggestions. Soot would be the best to describe it. I'm leaning towards wrong pitched prop. The previous owner replaced the factory prop w/ a 3 blade and its probably the wrong pitch because the max RPM is only about 3000. The bottom and prop were scraped about 3 mo's. ago.
more than likely the prop.
since you said the po changed the prop, that is the most likely culprit. the Gm series should be able to rev fully loaded 3550 to 3650 rpm. i don't know why some people try to put 3 bladed props on a small engine. but i guess some folks always have to be f***king with something that ain't broke. go to the yanmarhelp.com site and you can get the proper dia/pitch setup for you engine.
since you said the po changed the prop, that is the most likely culprit. the Gm series should be able to rev fully loaded 3550 to 3650 rpm. i don't know why some people try to put 3 bladed props on a small engine. but i guess some folks always have to be f***king with something that ain't broke. go to the yanmarhelp.com site and you can get the proper dia/pitch setup for you engine.
Capn jim prop ?
I found a 2 blade prop. in 1 of the lockers I guesing its the original. May try that one ???
I found a 2 blade prop. in 1 of the lockers I guesing its the original. May try that one ???
don't just put it on!
the dia and pitch are usually stamped on the hub of the prop. such as on my original which has 16x10, which means 16"dia by 10" pitch. there are lots of combo's for dia and pitch for a given engine trans comb and clearance available for prop to spin. there are also parameters as to how much clearance should be given for tip of blade to hull surface.
the dia and pitch are usually stamped on the hub of the prop. such as on my original which has 16x10, which means 16"dia by 10" pitch. there are lots of combo's for dia and pitch for a given engine trans comb and clearance available for prop to spin. there are also parameters as to how much clearance should be given for tip of blade to hull surface.
I jusr checked the yanmar site
they list three different trans for the gm series. 15" prop with a 2.21 gear ratio, 15"/2.62 and 17"/3.22 they also had sail drive set ups but i don't believe o'day had any sail drives. so you see you can't just slap any old prop on that will fit the shaft.
you just gave engine size and year of boat. what size boat?
as i said my original prop was a 16/10 on a 2Qm15. don't remember gear ratio offhand but i'm sure it wouldn't match up to yours since full load rpms are drastically different.
they list three different trans for the gm series. 15" prop with a 2.21 gear ratio, 15"/2.62 and 17"/3.22 they also had sail drive set ups but i don't believe o'day had any sail drives. so you see you can't just slap any old prop on that will fit the shaft.
you just gave engine size and year of boat. what size boat?
as i said my original prop was a 16/10 on a 2Qm15. don't remember gear ratio offhand but i'm sure it wouldn't match up to yours since full load rpms are drastically different.
capn jim
A ok will look at the stamp on the hub first before installing. btw its an 87 o'day 322 32'
Thanks for all the help.
A ok will look at the stamp on the hub first before installing. btw its an 87 o'day 322 32'
Thanks for all the help.
Frank
You might want to post the question of what prop belongs on that 322 on the ODayowners.com site cause there's few regulars with that same boat and you'll get an answer quick.
BTW
I had a three blade prop to replace my original 2 blade and had the same problem and only relized it after installing a new tach and saw I could not get over 1500 rpms, the prop was pitched to high,I ended up putting the 2 blade back on and it works just fine.
RAD
Free Spirit ODay 32
You might want to post the question of what prop belongs on that 322 on the ODayowners.com site cause there's few regulars with that same boat and you'll get an answer quick.
BTW
I had a three blade prop to replace my original 2 blade and had the same problem and only relized it after installing a new tach and saw I could not get over 1500 rpms, the prop was pitched to high,I ended up putting the 2 blade back on and it works just fine.
RAD
Free Spirit ODay 32
- Status