Honda 45 running/starting issues

Tim M · 26 February 2010, 22:15

The Honda 45 (3 cylinder 4 stroke) that came with my Searider has had a bit of an issue since I bought it (although I've only used it twice before I refurbed it). Before I launched it for the first time today I ran it up on the trailer and sure enough it had the same problem as before. It's impossible to start at idle - needs choke and fast idle to get it going, even when warm. After that its not particularly keen running at idle - normally just stalls. It runs fine at high speed - same as in the water. It ran fine all the way to Cowes, but when it came to pottering around at slow speed it kept stalling.

My immediate though was carbs, so this afternoon I did a fairly quick clean of the internals - took them off the engine, took the float bowls off, took everything out, blasted some compressed air through, rinsed them with some WD40 then put them back together. Despite finding quite a bit of crap in there the engine is still not happy running at idle. I've fiddled with the mixture but that doesn't cure it.

I've got a mechanically minded friend having a look at it tomorrow, but any suggestions would be welcome in the meantime. Bare in mind my mechanical skills are very basic so please be kind!

Robbie Diesel · 26 February 2010, 22:48

Hi Tim, I had twin 45hp Hondas around about 10 years ago on a humber rib. They were fairly tatty, high hour engines that i got cheap and refurbished myself. But had one or two problems with them over the years. One of them would not start very well when it was hot, and balancing the carbs and re-setting the fuel air mixture screw settings cured that problem perfectly. But the second engine nearly drove me round the bend

It had a problem that sounds very similar to yours. It would run great and strong at speed but, slow down to idle and it would slowly die down untill it stalled. I re-set the carbs like i did on the other engine, no difference. I took the hood off and upped the idle speed a fair bit so there was no way it could stall, sounded great, put the hood on, took it for a run, pulled it back to idle, stalled AGAIN

Then i took it for a run with the hood off, and beleive it or not, it idled PERFECTLY! Put the hood back on, it would slowly die and stall.
To cut a long story short, the Exhaust had corroded through, and there was a small 5mm hole where the power head bolts to the block, The exhaust gas leaking out under the hood and was being ingested by the engine, and it won't idle very well with a build up of exhaust gas under the hood. It would have cost a FORTUNE to fix properly, so we just put a little Chemical Metal over the hole and it cured the problem fine, Idle was perfect after that. The engine ran great for many years after that. Anyway, perhaps worth trying a run without the hood on your engine, just to see if your engine has the same fault. Also if you are still having problems, Can i highly recommend giving Colin at Ardoran Marine in Oban a ring. He's a Honda 4 stroke expert and gave me loads of very helpful advice when i had my problems.

Hope this Helps

Robbie

Tim M · 26 February 2010, 23:09

Hi Robbie. Many thanks for that. Unfortunately I was running the engine with the hood off for most of the afternoon whilst tinkering with it and it still died. I too tried the idle trick, worked for a few Min's then went back to stalling. Do you happen to know off hand how many turns from all the way in you set the mixture screws? At the moment I'm 3 1/2 fulls turns from all the way in. I tried various settings but it didn't really make any difference.

Nos4r2 · 27 February 2010, 06:50

Quote:

Originally Posted by Tim M

Hi Robbie. Many thanks for that. Unfortunately I was running the engine with the hood off for most of the afternoon whilst tinkering with it and it still died. I too tried the idle trick, worked for a few Min's then went back to stalling. Do you happen to know off hand how many turns from all the way in you set the mixture screws? At the moment I'm 3 1/2 fulls turns from all the way in. I tried various settings but it didn't really make any difference.

What's the make on the carbs? Keihin or Mikuni?

Ribshop · 27 February 2010, 07:45

Hi Tim, when you put the carbs back on did you balance them?

Erin · 27 February 2010, 10:14

Just make sure the choke is coming off properly. We had a BF50 and a small white plastic clip that fits next to the choke solenoid came adrift and meant that the engine was always running on choke. It made it a bu**er to start and wouldn't run properly.

Tim M · 27 February 2010, 11:44

Nos, not sure, will check

Keiron, no. How do I do this?

Erin, choke is defiantly coming off

Ribshop · 27 February 2010, 12:11

You will need a set of vacuum gauges, its a 5 minute job, if you can run the boat over I don’t mind showing you how to do it. Just give me a bell before you come over I am a bit all over the place at the mo.

Tim M · 02 March 2010, 09:57

Thanks for the offer

It turned out the float in the top carb was sticking