stringer 800

[vicjunkie]

hi all,

I have been posting a long thread on BOC about my issues, and a member directed me here. here is where I am. boat is a 5.7 with a stringer 800 mechanical shift, low profile. I am overheating at anything over 2500rpms. Temp will slowly start to creep up, and I shut it down before it crests 200. I have been through all systems numerous times, here is what I have done so far.

1. replaced impeller
2. installed new manifolds and risers
3. checked exhaust shutters, they are there and functioning
4. installed new thermostat, have ran without thermostat installed, same results
5. installed new circulating pump on motor.
6. removed drain cocks from water jacket in the block, pulled thermo housing, water pump, temp sending unit, and flushed with a combination of water and compressed air, some rust scale came out, but nothing I would be concerned with.

I have a service manual, and did all of the troubleshooting tests it describes. I have adequate flow from the intermediate housing to the tsat housing, checked the flow to each manifold, my suction hose on my circ pump is not collapsing. I dont believe the temp sening unit and guage is bad, redings are to consistant.

Today I went back and rechecked everytihing and here is my question. I thought back, and remembered when I ran it on the muffs this spring, there was absolutely no water coming through the prop at any rpm, all of it was going out the exhaust relief ports. So, I removed my prop, started the boat and climbed into the water. No exhaust or water through prop. I ran it up to various rpms, and still nothing through the prop. I raised the unit, plugged thye relief ports with a rag, lowered it back down, and still noting through the prop. alot of exhaust gasses and water seem to be pushing throug the small gap between my intermediate housing and the upper unit. Is this my restriction, or is this normal? Many people are telling me this is normal, and exhaust gasses and water onlyu exit the prop when under way. Any help with this will be greatly appreciated, I have been fighting this for some time, and am begining to think i may never be able to enjoy this boat.

 

[Nivekt]

Re: stringer 800

I get lots of exhaust and water flow through my prop when I'm running on the muffs. How much will depend on your flow/pressure through your garden hose though. Have you taken an IR thermometer and aimed it at the temp sender to verify the actual temp is what your gauge is displaying?

 

[vicjunkie]

Re: stringer 800

no i dont hasve access to a temp gun, but i know that the temps are always normal until i run it up to 2500 rpms and then they climb. take the stat out, and temps are way down around 100. always heats up and then when i back it down to idle, it comes back down to 170 where it is supposed to be. guage seems to be very consistant, and i can tell by the feel of the manifolds that it is getting hotter than normal.It seems like when i have ran it on the muffs in the past, there was water flow from the prop, but cant be sure, this is only my second season with a stringer.

 

[Nivekt]

Re: stringer 800

I would still recommend getting an IR gun to be sure. I had a similar issue to yours last year and I ended up having a faulty sender. I was able to diagnose my issue with an IR gun. Here is a video I made a few minutes ago of mine running on a hose with good water pressure.

Stringer running on the hose at idle. - YouTube

 

[Howard Sterndrive]

Re: stringer 800

grease the swivel bearing- your impeller is sucking exhaust gases.
6 shots of grease will seal it up

look at item 37 on this pic - there's a hole there - look in it and you'll see the grease fitting- needs to be greased twice a season
http://img167.imageshack.us/img167/3559/upperiw1.jpg

 

[vicjunkie]

Re: stringer 800

I will grease the swival bearing. I ordered a heat gun it is on the way. My outdrive didnt run water out of the prop like the one on the video does, and thanks for posting that. so does anyone have a answer as to if exhaust and water should flow out of the prop while in the water and stationary?

 

[Boomyal]

Re: stringer 800

At an idle, in the water, most all of your exhaust is going to exit via the relief ports in the Intermediate housing. That would be the path of least resistance as those ports are above and before the prop hub. I would assume that any water from the impeller would exit there as well. Once the boat is underway, there would be a vacuum created at the rear of the prop and water and exhaust would be easily scavenged there.

In the driveway, on muffs (or equiv) water and exhaust will exit the prop hub as well.

 

[vicjunkie]

Re: stringer 800

Greased swivel bearing, no help. Shes at home in driveway. I started her up on the muffs today, and all water and exhaust is coming from the front of the lower unit from the slit just below where i greased the swivel bearing. None from the prop, exhaust or water.

 

[Boomyal]

Re: stringer 800

Greased swivel bearing, no help. Shes at home in driveway. I started her up on the muffs today, and all water and exhaust is coming from the front of the lower unit from the slit just below where i greased the swivel bearing. None from the prop, exhaust or water.

You should not see any water coming out at the swivel point of the drive. There is something you missed when you replaced the impeller.

 

[vicjunkie]

Re: stringer 800

The water is not coming from where the upper and lower meet, but a opening on the transom side of the drive just below the hole where you grease the bearing. It is about 1/4" wide, and runs all the way across the drive. Im going to remove the drive tomorrow and see what ive got

 

[Boomyal]

Re: stringer 800

The water is not coming from where the upper and lower meet, but a opening on the transom side of the drive just below the hole where you grease the bearing. It is about 1/4" wide, and runs all the way across the drive. Im going to remove the drive tomorrow and see what ive got

Post a picture before you remove the drive. I do not have a clear picture of what you are speaking of. And I do not know what bearing you are talking about.

On the muffs, most of the water will come out of the relief ports at the bottom of the intermediate housing exhaust port. A smaller trickle will come out of the propeller hub.

 

[Howard Sterndrive]

Re: stringer 800

The water is not coming from where the upper and lower meet, but a opening on the transom side of the drive just below the hole where you grease the bearing. It is about 1/4" wide, and runs all the way across the drive. Im going to remove the drive tomorrow and see what ive got

it's supposed to come out there - there's a big "grate" in the anode at the bottom of the intermediate.

See all those holes.... that's for exhaust and water to come out.
Otherwise the engine wouldn't start in the lake -there's too much back pressure at the depth of the prop.

 

[Nivekt]

Re: stringer 800

The water is not coming from where the upper and lower meet, but a opening on the transom side of the drive just below the hole where you grease the bearing. It is about 1/4" wide, and runs all the way across the drive. Im going to remove the drive tomorrow and see what ive got

Your talking about the exit port beneath the huge anode under the intermediate(just like in my video above at :26 seconds right?). Water coming from there is normal. How is your water pressure from the hose. Does it trickle or do you get a strong stream? Perhaps post some videos of your hose pressure and the drive running on the hose so we can get a better idea of flow. Also, do you get water coming out of the little tattle tell hole in the upper part of the intermediate and into the upper gear case?(like my video at :39 seconds?)

 

[vicjunkie]

Re: stringer 800

Water is coming from the relif ports , i understand that, but none from the prop. The hole im talking about is where you grease the swivel bearing, just below that. My pressure is strong, and water is pouring out the relief ports. I will post a video in the morning

 

[vicjunkie]

Re: stringer 800

here is the video of my drive at idle. where i point to is where all the exhaust and water are exiting

IMG 0025 - YouTube

 

[vicjunkie]

Re: stringer 800

ok,

I figured out what the slot is I am refering to. it is the front anode slot in the exhaust housing. Apparently it is missing, and I dont remember it ever being there. This wouldnt cause me to run hot would it? I went ahead and dropped the unit,and there are no obstructions at all in the lower.

 

[Boomyal]

Re: stringer 800

I just had mine running yesterday in the same config as you, except I have the flush attachment on the right trunnion. I also think that you have your water turned on higher than I turn mine on. Most of my water exits in the same fashion as your video shows but I get a slightly larger flow out of the prop exhaust (my prop is off also). I did not bend down to see the force of any exhaust exiting down there. I also have some water bleeding out the intake holes that your muffs are covering.

All that being said, here is what the book has to say about it all:

TAKE NOTE: It is possible to install the water pump without servicing the swivel housing. However, if it not performed, the new pump may not move enough water to the engine and replacement of the pump will not give the desired results.

The exhaust housing is not considered part of the water pump repair. However, the housing must be removed in order to remove the swivel housing.

Therefore, remove the exhaust housing, see Exhaust Housing Removal, Section 10-35

The swivel housing plays a critical role in the cooling system. Any exhaust gases or leakage at the swivel housing will cause failure of a new water pump.

Therefore, remove the swivel housing; see Section 10-36.

 

[Howard Sterndrive]

Re: stringer 800

everything fine in that video but you might as well replace that anode they're cheap insurance against corrosion.

I still think your impeller is sucking exhaust

A piece of clear tubing before the thermostat housing will verify or eliminate. e.g. Mercruiser 5.7 cooling bubbles - YouTube

that's a merc, but same idea- right around 2500rpm under load is where back pressure in the lower unit starts to build. My Alpha One Gen 2 Merc had the same issue. Lots of threads about it happening on stringers.
Grease usually seals the stringers, but you may have a damaged seal there or missing the big nylon washer or something. Or the upper isn't shimmed into the lower correctly - although the upper gearcase would be full of milky water by now if it was floating that much.

 

[vicjunkie]

Re: stringer 800

Ok, I have the unit off, I looked at the seals in the swivel housing, they both look good, top and bottom. the nylon washer is in place, and seems fine. This is not the origional upper unit to this drive. i replaced it last season with a used drive. This was approx 80 hrs. of operation before the overheating started. I do have a very small amount of water getting into the upper somehow. It is slightly milky. although boat has been in the slip for about 4 weeks now, and I have ran prob around 25 hrs this season. We just took about a 50 mile round trip on thursday of this last week.I want to reseal the whole thing, to keep the water out of the upper and fix this exhaust issue. can anyone tell me where to start?

 

[Boomyal]

Re: stringer 800

I'm beginning to wonder if it is a problem with your outdrive at all? I forgot, if you even mentioned it, can you get the heat to rise while on the muffs? If so, you ought to get yourself a trunnion flush kit. That will make sure that your engine gets sufficient water. Then if you still have a temperature issue, look at the engine and plumbing.

First, however, I would wait til you get your IR temperature gun.