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Re: 350 MAG Backfire Through Intake
Update: When I had the cap off I happened to take a picture of the top of the distributor. I zoomed in to what I thought looked like a crack where the cap mounts. Sure enough, the distributor base was cracked at the screw hole. I started doing some research and found that this is a common issue in the automotive world. So common, they make an aftermarket half-moon shaped bracket that fits under the top of the distributor and is used to screw the cap to. For $30 I figured I'd give it a try (the alternative being a whole new distributor). It's a bit of a PITA to get mounted but once installed, my backfire issue was gone. So my guess would be over time the cap was loosening on the one side and becoming misaligned, creating the backfire. 
JimGuy341
5 ·
Re: Rinker 350/360 2007+ Random Topics
No it’s 46 km/h @kordo
Boat performs totally different this year - I don’t know what % to allocate to bottom paint vs the larger trim tabs vs the new dinghy lift but I am really happy. Boat pops up on plane effortlessly despite the dinghy.
Boat performs totally different this year - I don’t know what % to allocate to bottom paint vs the larger trim tabs vs the new dinghy lift but I am really happy. Boat pops up on plane effortlessly despite the dinghy.
I am having so much fun with this I may add a transom extension to see what impact it has. Fairline Targa 45 has this setup which would be very easy to duplicate:
YYZRC
1 ·
Re: 2004 270 FV Main switch panel - anywhere to get it Oct 2024?
Personally I am more of a fan of a new panel out of metal or carbon fiber than wrap. I did both. Heat and sunlight through the windshield makes the wrap very brittle after a little. It is easy to nick or tear especially around the screws. Putting it on is do able but tough even for experienced installers. The hard part is getting the wrap to stretch enough on the inside curves for the guages. Some brands of wrap heat up and stretch better than others. So if you go that route get the best quality possible, order extra and be gentle with the screws.
davidbrooks
1 ·
Re: 350 MAG Backfire Through Intake
Slop in timing chain or distributor gear worn, or exhaust valve not seating completely.
Get a leak down on each cylinder. An exhaust lifter could be weak and losing pressure at that rpm on an individual cylinder, and perhaps have tiny debris in its port, which can make it sporadic.
Given the relationship with the cap and rotor, it would more likely have to do with the timing chain.. those dang things have nylon between links to keep them quieter, but which wear as you can imagine.. that allows tiny amounts of slop that create more slop over time and which is apparent at higher rpms. It's a six pack job- no more than a couple hours. You can test for slop by pulling cap off and watching the rotor button while hand turning the engine and observing how quickly the rotor responds when you turn engine- should be instant. That's just a shade tree test, though.
Look at the caps inside to see if there is indication of spark spray- if the cap has any age on it there should be pretty clear little lines across each point and uniformly worn- you'll be able to see, if you're lucky, constant fire from one point to the next indicating where it drags spark between the points, in affect firing them both at same time or pretty dang close to same time, and which indicates back to slop in a specific link or series of links in the timing chain.
If you have to replace the chain, get a good one. Double roller without nylon inserts/liners...
One more thing- get a vacuum gauge on that thing. Having two matching engines you should have equal load on each engine at same load and rpm.. if one is less vacuum you have a leak that rears it's head when drawing the most (not loaded down and steady rpm), and that causes air:fuel issues with ignition still happening when the intake valve opens (being rich) and ignites the intake runner- hence backfire through intake.
Alright, one more one more thing: Your timing could simply be off, too. A degree advanced or retarded could cause spark spray.
A backfire through the intake is NOT to be taken lightly on a boat. Things can go boom quickly.
Get a leak down on each cylinder. An exhaust lifter could be weak and losing pressure at that rpm on an individual cylinder, and perhaps have tiny debris in its port, which can make it sporadic.
Given the relationship with the cap and rotor, it would more likely have to do with the timing chain.. those dang things have nylon between links to keep them quieter, but which wear as you can imagine.. that allows tiny amounts of slop that create more slop over time and which is apparent at higher rpms. It's a six pack job- no more than a couple hours. You can test for slop by pulling cap off and watching the rotor button while hand turning the engine and observing how quickly the rotor responds when you turn engine- should be instant. That's just a shade tree test, though.
Look at the caps inside to see if there is indication of spark spray- if the cap has any age on it there should be pretty clear little lines across each point and uniformly worn- you'll be able to see, if you're lucky, constant fire from one point to the next indicating where it drags spark between the points, in affect firing them both at same time or pretty dang close to same time, and which indicates back to slop in a specific link or series of links in the timing chain.
If you have to replace the chain, get a good one. Double roller without nylon inserts/liners...
One more thing- get a vacuum gauge on that thing. Having two matching engines you should have equal load on each engine at same load and rpm.. if one is less vacuum you have a leak that rears it's head when drawing the most (not loaded down and steady rpm), and that causes air:fuel issues with ignition still happening when the intake valve opens (being rich) and ignites the intake runner- hence backfire through intake.
Alright, one more one more thing: Your timing could simply be off, too. A degree advanced or retarded could cause spark spray.
A backfire through the intake is NOT to be taken lightly on a boat. Things can go boom quickly.
212rowboat
2 ·
Re: What did you do to your boat today
I couldn’t find my post on this Maguire's Ceramic Wax. I wanted to do a follow up. The hull still looks great, slightly less shine from when I applied it at the beginning of the season but the water still beads. I’m going to reapply before she gets wrapped and then again in spring time. I put it on without water, just spray on and wipe off.⚓️
Below is the link, it’s definitely gone up in price….
https://a.co/d/ckcvzmf
Below is the link, it’s definitely gone up in price….
https://a.co/d/ckcvzmf
aero3113
1 ·
Re: Cruisair AC won't heat -- stuck reverse-cycle valve?
Last winter in Virginia during the refit project, I ran reverse-cycle heat almost the entire winter. They did fine until the river got too cold -- maybe 45*F. I think they were all working at that time.
LaRea
1 ·
Re: Meet the new La Rea!
As a comparison on our Mainship 390 trawler on the loop, a single Yanmar Diesel 370 HP running at 1750 RPM, 9.5 MPH, our average for the whole loop was 0.44 GPM. We ran at this speed for at least 95% of the time and agree with @LaRea it becomes an enjoyable way to cruise.
Grahamu
2 ·
Re: Meet the new La Rea!
Was hoping nobody would ask! 
My original projections were pretty close. With the genny running:
600 RPM, 7 mph, 2.6 mpg (only when required by law)
800 RPM, 9.5 mph, 1.9 mpg (80% of the time)
2000 RPM, 26 mph, 0.5 mpg (when I want to splurge or need to outrun weather)
To be honest, I have grown to love the long passages going 8 knots. It's just me and Diane chilling at the bridge -- peaceful, quiet and calm. We talk and enjoy the scenery. On longer legs, she reads or writes and I can usually work on my laptop (billable hours when I can, or planning the next day's trip). It's a different style of boating from when i was working full-time.
My original projections were pretty close. With the genny running: 600 RPM, 7 mph, 2.6 mpg (only when required by law)
800 RPM, 9.5 mph, 1.9 mpg (80% of the time)
2000 RPM, 26 mph, 0.5 mpg (when I want to splurge or need to outrun weather)
To be honest, I have grown to love the long passages going 8 knots. It's just me and Diane chilling at the bridge -- peaceful, quiet and calm. We talk and enjoy the scenery. On longer legs, she reads or writes and I can usually work on my laptop (billable hours when I can, or planning the next day's trip). It's a different style of boating from when i was working full-time.
LaRea
4 ·