Manifold and Riser again - urgent opinion needed

[oGaryo]

Hi peeps.. so, took the temporary cheapskates route and bodged the riser to manifold gasket with Loctite 5926 rtv sealant thinking it'd get me through this weekend as I couldn't get the mating faces level so dry fitting wasn't an option.. fired her up after letting it cure overnight and all looked ok apart from water spitting from the port transome exhaust.. prior to the change there was a very small amount from the port exhaust, gushing water from the starboard side and a dribble from the prop. ran for a further 5 mins and the water from the port side increased fairly significantly... do I have a leak from the riser or is it a case of more water allowed through after clearing the water jacket equalling increased back pressure to both transome exhaust outlets?

I've cancelled this weekend to be safe and have a quote to replace both the riser and the manifold for £280 + vat including all gaskets from Trickett Marine... so will now go for that and put the above down to (in)experience! still would like to know if the symptoms are leak or normal so I know what to watch out for when replacing with new.

Enjoy your weekend's boating everyone whilst I do DIY instead

 

[ChrisKaye]

Don't feel too bad, I have loads of stuff to do on the boat but that's in the Isle of Wight and I'm 60miles away, but instead I'll be DIY-ing too, I will be up a scaffold hacking out and re-pointing and earning brownie points

 

[spannerman]

It doesn't have any bearing as all the water and exhaust from the two risers meet at the bottom of the downpipe and goes through the transom and then divides into port and starboard bypass ports and main exhuast through the prop.
They don't always deliver equal amounts from both sides when run on a hose.

 

[oGaryo]

It doesn't have any bearing as all the water and exhaust from the two risers meet at the bottom of the downpipe and goes through the transom and then divides into port and starboard bypass ports and main exhuast through the prop.
They don't always deliver equal amounts from both sides when run on a hose.

thanks but this is a 3.0lx with single riser... presume the same stands though and there'll be a y pipe or something in the lower exhaust that splits the flow as you say. I checked the flapper btw and that looks fine but again, I guess that wouldn't have a bearing either.. just strange that the water flow from the port side clearly increased after 5 mins or so

Have just placed the order... GLM parts but half the price of OEM, arrives Monday so should be back on the water ready for next weekend

 

[tinkicker0]

I take you are on muffs?

Normal for more water to exit stbd bypass port when on muffs. Water comes from port side riser, down inclined exhaust tube and is carried across the exhaust chamber under inertia to the exit the stbd port.

RTV??? naughty boy

 

[Solitaire]

Hi peeps.. so, took the temporary cheapskates route and bodged the riser to manifold gasket with Loctite 5926 rtv sealant thinking it'd get me through this weekend as I couldn't get the mating faces level so dry fitting wasn't an option.. fired her up after letting it cure overnight and all looked ok apart from water spitting from the port transome exhaust.. prior to the change there was a very small amount from the port exhaust, gushing water from the starboard side and a dribble from the prop.

I can say that from bitter, and costly experience, do not take the "cheapskates" route where your risers etc. are concerned.

If you get a leak, water can find it's way into the engine and hay presto we have hydro-lock. Result, new engine. I know!!!

 

[oGaryo]

I take you are on muffs?

Normal for more water to exit stbd bypass port when on muffs. Water comes from port side riser, down inclined exhaust tube and is carried across the exhaust chamber under inertia to the exit the stbd port.

RTV??? naughty boy

yep, was on the muffs TK... have been told not to use rtv on that gasket but it was all I had so thought sod it, it'll be ok for 1 weekend.. naughty boy indeed

 

[oGaryo]

I can say that from bitter, and costly experience, do not take the "cheapskates" route where your risers etc. are concerned.

If you get a leak, water can find it's way into the engine and hay presto we have hydro-lock. Result, new engine. I know!!!

advice taken thanks.. parts arriving Monday and we'll then see if this overheat issue is no more, if not, I guess it'll be time to resort to Fernox DS-3through the engine waterways but I least I'll have discounted anything to do with the riser or manifold... there no rusty valve stems btw so I don't thinnk I've had a long term issue of leakage back in to the cylinder, just clogged water jacket and a bit of elbow gasket seepage hopefully

 

[carlton]

Gary - I hammered out a reply to your previous post about using Fernox but held back from posting it as it sounded a bit negative and full of doom, containing such things as 'buy new mans and risers - don't take the risk with your engine - the end of the world is nigh' and suchlike.

However, I'm pleased you've decided to follow the safer (albeit more expensive in the short term) route.

(Edit: I even included a link to Tricketts!)

 

[oGaryo]

Gary - I hammered out a reply to your previous post about using Fernox but held back from posting it as it sounded a bit negative and full of doom, containing such things as 'buy new mans and risers - don't take the risk with your engine - the end of the world is nigh' and suchlike.

However, I'm pleased you've decided to follow the safer (albeit more expensive in the short term) route.

(Edit: I even included a link to Tricketts!)

yep, would have saved a load of gasket scraping with stanley knife blades but good experience all the same.. may still need the ds3 to clear out the engine waterways though so not all wasted effort.

Have just taken off the manifold and riser and that blue rtv is rubbish on these green gaskets, definitely leaked again so it was right to shut down as soon as I saw a change in water flow at the back end,

Lesson learned and a hydrolocked engine avoided... just

good excuse to fit the new speakers, propex heater, second battery, inverter and 12v TV in the cuddy this weekend instead.... keeping the youngsters warm and entertained is almost as never ending as tinkering with engines. lol

 

[tinkicker0]

yep, would have saved a load of gasket scraping with stanley knife blades but good experience all the same.. may still need the ds3 to clear out the engine waterways though so not all wasted effort.

Have just taken off the manifold and riser and that blue rtv is rubbish on these green gaskets, definitely leaked again so it was right to shut down as soon as I saw a change in water flow at the back end,

Lesson learned and a hydrolocked engine avoided... just

good excuse to fit the new speakers, propex heater, second battery, inverter and 12v TV in the cuddy this weekend instead.... keeping the youngsters warm and entertained is almost as never ending as tinkering with engines. lol

I always use Threebond 1215 on water gaskets.

 

[STEVEDUNSTABLE]

yep, would have saved a load of gasket scraping with stanley knife blades but good experience all the same.. may still need the ds3 to clear out the engine waterways though so not all wasted effort.

Have just taken off the manifold and riser and that blue rtv is rubbish on these green gaskets, definitely leaked again so it was right to shut down as soon as I saw a change in water flow at the back end,

Lesson learned and a hydrolocked engine avoided... just

good excuse to fit the new speakers, propex heater, second battery, inverter and 12v TV in the cuddy this weekend instead.... keeping the youngsters warm and entertained is almost as never ending as tinkering with engines. lol

hi gary.......get your prorities right ..... SOD the engine probs GET THE BBQ sorted !!!!!!!.....ps. did you find where the fuel fumes were coming from (other than "somewhere near the bbq")!!!!!!! ?

 

[oGaryo]

hi gary.......get your prorities right ..... SOD the engine probs GET THE BBQ sorted !!!!!!!.....ps. did you find where the fuel fumes were coming from (other than "somewhere near the bbq")!!!!!!! ?

Both sorted... bbq steady as a rock and bought a couple of those lighters with a long extension to get in the hole to light the damn thing.. a quick tweak of the fuel/water separater sorted the fuel smell issue, was some slight seepage from there

 

[oGaryo]

I always use Threebond 1215 on water gaskets.

Just found some Loctitie 5922 in the garage .. not rtv so doesn't set, would have no doubt done the job but sort of glad I didn't find it if you know what I mean..

 

[spannerman]

thanks but this is a 3.0lx with single riser... presume the same stands though and there'll be a y pipe or something in the lower exhaust that splits the flow as you say. I checked the flapper btw and that looks fine but again, I guess that wouldn't have a bearing either.. just strange that the water flow from the port side clearly increased after 5 mins or so

The waterways split inside the transom shield itself irrespective of which motor is install 4/6/8 cyl, the reason the flow increased after 5 mins is most likely that the thermostat opened, the seawater comes into the block and and some is lead off so there is constant flow to cool the exhaust manifold and riser. The water in the block just circulates by means of the waterpump on the front of the engine, when the stat opens you then have increased flow as the engine pump is now also pushing the water from the block out through the exhaust, in addition to the pump in the drive pushing it in.
Its very common for the riser on 3.0 engines to rust up and block the water passages causing overheating, I have changed many because of this.